Leskille/code_chall

1prob_desc_description,clean_tags,labels2"Thanks to the Doctor's help, the rebels managed to steal enough gold to launch a full-scale attack on the Empire! However, Darth Vader is looking for revenge and wants to take back his gold.The rebels have hidden the gold in various bases throughout the galaxy. Darth Vader and the Empire are looking to send out their spaceships to attack these bases.The galaxy can be represented as an undirected graph with $$$n$$$ planets (nodes) and $$$m$$$ wormholes (edges), each connecting two planets.A total of $$$s$$$ empire spaceships and $$$b$$$ rebel bases are located at different planets in the galaxy.Each spaceship is given a location $$$x$$$, denoting the index of the planet on which it is located, an attacking strength $$$a$$$, and a certain amount of fuel $$$f$$$.Each base is given a location $$$x$$$, and a defensive strength $$$d$$$.A spaceship can attack a base if both of these conditions hold:   the spaceship's attacking strength is greater or equal than the defensive strength of the base  the spaceship's fuel is greater or equal to the shortest distance, computed as the number of wormholes, between the spaceship's planet and the base's planet Vader is very particular about his attacking formations. He requires that each spaceship is to attack at most one base and that each base is to be attacked by at most one spaceship.Vader knows that the rebels have hidden $$$k$$$ gold in each base, so he will assign the spaceships to attack bases in such a way that maximizes the number of bases attacked.Therefore, for each base that is attacked, the rebels lose $$$k$$$ gold.However, the rebels have the ability to create any number of dummy bases. With the Doctor's help, these bases would exist beyond space and time, so all spaceship can reach them and attack them. Moreover, a dummy base is designed to seem irresistible: that is, it will always be attacked by some spaceship.Of course, dummy bases do not contain any gold, but creating such a dummy base costs $$$h$$$ gold.What is the minimum gold the rebels can lose if they create an optimal number of dummy bases?",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"3"Professor Dumbledore is helping Harry destroy the Horcruxes. He went to Gaunt Shack as he suspected a Horcrux to be present there. He saw Marvolo Gaunt's Ring and identified it as a Horcrux. Although he destroyed it, he is still affected by its curse. Professor Snape is helping Dumbledore remove the curse. For this, he wants to give Dumbledore exactly x drops of the potion he made. Value of x is calculated as maximum of p·ai + q·aj + r·ak for given p, q, r and array a1, a2, ... an such that 1 ≤ i ≤ j ≤ k ≤ n. Help Snape find the value of x. Do note that the value of x may be negative.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"4"Is it rated?Here it is. The Ultimate Question of Competitive Programming, Codeforces, and Everything. And you are here to answer it.Another Codeforces round has been conducted. No two participants have the same number of points. For each participant, from the top to the bottom of the standings, their rating before and after the round is known.It's known that if at least one participant's rating has changed, then the round was rated for sure.It's also known that if the round was rated and a participant with lower rating took a better place in the standings than a participant with higher rating, then at least one round participant's rating has changed.In this problem, you should not make any other assumptions about the rating system.Determine if the current round is rated, unrated, or it's impossible to determine whether it is rated of not.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"5"Saitama accidentally destroyed a hotel again. To repay the hotel company, Genos has volunteered to operate an elevator in one of its other hotels. The elevator is special — it starts on the top floor, can only move down, and has infinite capacity. Floors are numbered from 0 to s and elevator initially starts on floor s at time 0.The elevator takes exactly 1 second to move down exactly 1 floor and negligible time to pick up passengers. Genos is given a list detailing when and on which floor passengers arrive. Please determine how long in seconds it will take Genos to bring all passengers to floor 0.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"6"You are given two integers $$$n$$$ and $$$k$$$.You should create an array of $$$n$$$ positive integers $$$a_1, a_2, \dots, a_n$$$ such that the sum $$$(a_1 + a_2 + \dots + a_n)$$$ is divisible by $$$k$$$ and maximum element in $$$a$$$ is minimum possible.What is the minimum possible maximum element in $$$a$$$?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"7"You are given string $$$s$$$ of length $$$n$$$ consisting of 0-s and 1-s. You build an infinite string $$$t$$$ as a concatenation of an infinite number of strings $$$s$$$, or $$$t = ssss \dots$$$ For example, if $$$s =$$$ 10010, then $$$t =$$$ 100101001010010...Calculate the number of prefixes of $$$t$$$ with balance equal to $$$x$$$. The balance of some string $$$q$$$ is equal to $$$cnt_{0, q} - cnt_{1, q}$$$, where $$$cnt_{0, q}$$$ is the number of occurrences of 0 in $$$q$$$, and $$$cnt_{1, q}$$$ is the number of occurrences of 1 in $$$q$$$. The number of such prefixes can be infinite; if it is so, you must say that.A prefix is a string consisting of several first letters of a given string, without any reorders. An empty prefix is also a valid prefix. For example, the string ""abcd"" has 5 prefixes: empty string, ""a"", ""ab"", ""abc"" and ""abcd"".","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"8"Vasya has his favourite number $$$n$$$. He wants to split it to some non-zero digits. It means, that he wants to choose some digits $$$d_1, d_2, \ldots, d_k$$$, such that $$$1 \leq d_i \leq 9$$$ for all $$$i$$$ and $$$d_1 + d_2 + \ldots + d_k = n$$$.Vasya likes beauty in everything, so he wants to find any solution with the minimal possible number of different digits among $$$d_1, d_2, \ldots, d_k$$$. Help him!",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"9"Alice has written a program and now tries to improve its readability. One of the ways to improve readability is to give sensible names to the variables, so now Alice wants to rename some variables in her program. In her IDE there is a command called ""massive refactoring"", which can replace names of many variable in just one run. To use it, Alice needs to select two strings $$$s$$$ and $$$t$$$ and after that for each variable the following algorithm is performed: if the variable's name contains $$$s$$$ as a substring, then the first (and only first) occurrence of $$$s$$$ is replaced with $$$t$$$. If the name doesn't contain $$$s$$$, then this variable's name stays the same.The list of variables is known and for each variable both the initial name and the name Alice wants this variable change to are known. Moreover, for each variable the lengths of the initial name and the target name are equal (otherwise the alignment of the code could become broken). You need to perform renaming of all variables in exactly one run of the massive refactoring command or determine that it is impossible.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"10"Find the number of k-divisible numbers on the segment [a, b]. In other words you need to find the number of such integer values x that a ≤ x ≤ b and x is divisible by k.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"11Berland crossword is a puzzle that is solved on a square grid with $$$n$$$ rows and $$$n$$$ columns. Initially all the cells are white.To solve the puzzle one has to color some cells on the border of the grid black in such a way that:   exactly $$$U$$$ cells in the top row are black;  exactly $$$R$$$ cells in the rightmost column are black;  exactly $$$D$$$ cells in the bottom row are black;  exactly $$$L$$$ cells in the leftmost column are black. Note that you can color zero cells black and leave every cell white.Your task is to check if there exists a solution to the given puzzle.,[],"[0, 0, 0, 0, 0, 0, 0, 0]"12"One of Timofey's birthday presents is a colourbook in a shape of an infinite plane. On the plane n rectangles with sides parallel to coordinate axes are situated. All sides of the rectangles have odd length. Rectangles cannot intersect, but they can touch each other.Help Timofey to color his rectangles in 4 different colors in such a way that every two rectangles touching each other by side would have different color, or determine that it is impossible.Two rectangles intersect if their intersection has positive area. Two rectangles touch by sides if there is a pair of sides such that their intersection has non-zero length    The picture corresponds to the first example ",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"13"Given a cyclic array $$$a$$$ of size $$$n$$$, where $$$a_i$$$ is the value of $$$a$$$ in the $$$i$$$-th position, there may be repeated values. Let us define that a permutation of $$$a$$$ is equal to another permutation of $$$a$$$ if and only if their values are the same for each position $$$i$$$ or we can transform them to each other by performing some cyclic rotation. Let us define for a cyclic array $$$b$$$ its number of components as the number of connected components in a graph, where the vertices are the positions of $$$b$$$ and we add an edge between each pair of adjacent positions of $$$b$$$ with equal values (note that in a cyclic array the first and last position are also adjacents).Find the expected value of components of a permutation of $$$a$$$ if we select it equiprobably over the set of all the different permutations of $$$a$$$.","['math', 'number theory', 'probabilities']","[0, 0, 0, 1, 1, 1, 0, 0]"14"Sam lives in Awesomeburg, its downtown has a triangular shape. Also, the following is true about the triangle:  its vertices have integer coordinates,  the coordinates of vertices are non-negative, and  its vertices are not on a single line. He calls a point on the downtown's border (that is the border of the triangle) safe if he can reach this point from at least one point of the line $$$y = 0$$$ walking along some straight line, without crossing the interior of the triangle.  In the picture the downtown is marked with grey color. The first path is invalid because it does not go along a straight line. The second path is invalid because it intersects with the interior of the downtown. The third and fourth paths are correct. Find the total length of the unsafe parts of the downtown border. It can be proven that these parts are segments and their number is finite.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"15"Ilya is working for the company that constructs robots. Ilya writes programs for entertainment robots, and his current project is ""Bob"", a new-generation game robot. Ilya's boss wants to know his progress so far. Especially he is interested if Bob is better at playing different games than the previous model, ""Alice"". So now Ilya wants to compare his robots' performance in a simple game called ""1-2-3"". This game is similar to the ""Rock-Paper-Scissors"" game: both robots secretly choose a number from the set {1, 2, 3} and say it at the same moment. If both robots choose the same number, then it's a draw and noone gets any points. But if chosen numbers are different, then one of the robots gets a point: 3 beats 2, 2 beats 1 and 1 beats 3. Both robots' programs make them choose their numbers in such a way that their choice in (i + 1)-th game depends only on the numbers chosen by them in i-th game. Ilya knows that the robots will play k games, Alice will choose number a in the first game, and Bob will choose b in the first game. He also knows both robots' programs and can tell what each robot will choose depending on their choices in previous game. Ilya doesn't want to wait until robots play all k games, so he asks you to predict the number of points they will have after the final game. ",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"16"While Patrick was gone shopping, Spongebob decided to play a little trick on his friend. The naughty Sponge browsed through Patrick's personal stuff and found a sequence a1, a2, ..., am of length m, consisting of integers from 1 to n, not necessarily distinct. Then he picked some sequence f1, f2, ..., fn of length n and for each number ai got number bi = fai. To finish the prank he erased the initial sequence ai.It's hard to express how sad Patrick was when he returned home from shopping! We will just say that Spongebob immediately got really sorry about what he has done and he is now trying to restore the original sequence. Help him do this or determine that this is impossible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"17"Paladin Manao caught the trail of the ancient Book of Evil in a swampy area. This area contains n settlements numbered from 1 to n. Moving through the swamp is very difficult, so people tramped exactly n - 1 paths. Each of these paths connects some pair of settlements and is bidirectional. Moreover, it is possible to reach any settlement from any other one by traversing one or several paths.The distance between two settlements is the minimum number of paths that have to be crossed to get from one settlement to the other one. Manao knows that the Book of Evil has got a damage range d. This means that if the Book of Evil is located in some settlement, its damage (for example, emergence of ghosts and werewolves) affects other settlements at distance d or less from the settlement where the Book resides.Manao has heard of m settlements affected by the Book of Evil. Their numbers are p1, p2, ..., pm. Note that the Book may be affecting other settlements as well, but this has not been detected yet. Manao wants to determine which settlements may contain the Book. Help him with this difficult task.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"18"After the mysterious disappearance of Ashish, his two favourite disciples Ishika and Hriday, were each left with one half of a secret message. These messages can each be represented by a permutation of size $$$n$$$. Let's call them $$$a$$$ and $$$b$$$.Note that a permutation of $$$n$$$ elements is a sequence of numbers $$$a_1, a_2, \ldots, a_n$$$, in which every number from $$$1$$$ to $$$n$$$ appears exactly once. The message can be decoded by an arrangement of sequence $$$a$$$ and $$$b$$$, such that the number of matching pairs of elements between them is maximum. A pair of elements $$$a_i$$$ and $$$b_j$$$ is said to match if:   $$$i = j$$$, that is, they are at the same index.  $$$a_i = b_j$$$ His two disciples are allowed to perform the following operation any number of times:   choose a number $$$k$$$ and cyclically shift one of the permutations to the left or right $$$k$$$ times. A single cyclic shift to the left on any permutation $$$c$$$ is an operation that sets $$$c_1:=c_2, c_2:=c_3, \ldots, c_n:=c_1$$$ simultaneously. Likewise, a single cyclic shift to the right on any permutation $$$c$$$ is an operation that sets $$$c_1:=c_n, c_2:=c_1, \ldots, c_n:=c_{n-1}$$$ simultaneously.Help Ishika and Hriday find the maximum number of pairs of elements that match after performing the operation any (possibly zero) number of times.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"19"Asterix, Obelix and their temporary buddies Suffix and Prefix has finally found the Harmony temple. However, its doors were firmly locked and even Obelix had no luck opening them.A little later they found a string s, carved on a rock below the temple's gates. Asterix supposed that that's the password that opens the temple and read the string aloud. However, nothing happened. Then Asterix supposed that a password is some substring t of the string s.Prefix supposed that the substring t is the beginning of the string s; Suffix supposed that the substring t should be the end of the string s; and Obelix supposed that t should be located somewhere inside the string s, that is, t is neither its beginning, nor its end.Asterix chose the substring t so as to please all his companions. Besides, from all acceptable variants Asterix chose the longest one (as Asterix loves long strings). When Asterix read the substring t aloud, the temple doors opened. You know the string s. Find the substring t or determine that such substring does not exist and all that's been written above is just a nice legend.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"20"You are given an array $$$A$$$, consisting of $$$n$$$ positive integers $$$a_1, a_2, \dots, a_n$$$, and an array $$$B$$$, consisting of $$$m$$$ positive integers $$$b_1, b_2, \dots, b_m$$$. Choose some element $$$a$$$ of $$$A$$$ and some element $$$b$$$ of $$$B$$$ such that $$$a+b$$$ doesn't belong to $$$A$$$ and doesn't belong to $$$B$$$. For example, if $$$A = [2, 1, 7]$$$ and $$$B = [1, 3, 4]$$$, we can choose $$$1$$$ from $$$A$$$ and $$$4$$$ from $$$B$$$, as number $$$5 = 1 + 4$$$ doesn't belong to $$$A$$$ and doesn't belong to $$$B$$$. However, we can't choose $$$2$$$ from $$$A$$$ and $$$1$$$ from $$$B$$$, as $$$3 = 2 + 1$$$ belongs to $$$B$$$.It can be shown that such a pair exists. If there are multiple answers, print any.Choose and print any such two numbers.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"21"One drew a closed polyline on a plane, that consisted only of vertical and horizontal segments (parallel to the coordinate axes). The segments alternated between horizontal and vertical ones (a horizontal segment was always followed by a vertical one, and vice versa). The polyline did not contain strict self-intersections, which means that in case any two segments shared a common point, that point was an endpoint for both of them (please consult the examples in the notes section).Unfortunately, the polyline was erased, and you only know the lengths of the horizonal and vertical segments. Please construct any polyline matching the description with such segments, or determine that it does not exist.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"22"You are given an integer $$$n$$$. You have to construct a permutation of size $$$n$$$.A permutation is an array where each integer from $$$1$$$ to $$$s$$$ (where $$$s$$$ is the size of permutation) occurs exactly once. For example, $$$[2, 1, 4, 3]$$$ is a permutation of size $$$4$$$; $$$[1, 2, 4, 5, 3]$$$ is a permutation of size $$$5$$$; $$$[1, 4, 3]$$$ is not a permutation (the integer $$$2$$$ is absent), $$$[2, 1, 3, 1]$$$ is not a permutation (the integer $$$1$$$ appears twice).A subsegment of a permutation is a contiguous subsequence of that permutation. For example, the permutation $$$[2, 1, 4, 3]$$$ has $$$10$$$ subsegments: $$$[2]$$$, $$$[2, 1]$$$, $$$[2, 1, 4]$$$, $$$[2, 1, 4, 3]$$$, $$$[1]$$$, $$$[1, 4]$$$, $$$[1, 4, 3]$$$, $$$[4]$$$, $$$[4, 3]$$$ and $$$[3]$$$.The value of the permutation is the number of its subsegments which are also permutations. For example, the value of $$$[2, 1, 4, 3]$$$ is $$$3$$$ since the subsegments $$$[2, 1]$$$, $$$[1]$$$ and $$$[2, 1, 4, 3]$$$ are permutations.You have to construct a permutation of size $$$n$$$ with minimum possible value among all permutations of size $$$n$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"23"You are given a chess board with $$$n$$$ rows and $$$n$$$ columns. Initially all cells of the board are empty, and you have to put a white or a black knight into each cell of the board.A knight is a chess piece that can attack a piece in cell ($$$x_2$$$, $$$y_2$$$) from the cell ($$$x_1$$$, $$$y_1$$$) if one of the following conditions is met:  $$$|x_1 - x_2| = 2$$$ and $$$|y_1 - y_2| = 1$$$, or  $$$|x_1 - x_2| = 1$$$ and $$$|y_1 - y_2| = 2$$$. Here are some examples of which cells knight can attack. In each of the following pictures, if the knight is currently in the blue cell, it can attack all red cells (and only them).  A duel of knights is a pair of knights of different colors such that these knights attack each other. You have to put a knight (a white one or a black one) into each cell in such a way that the number of duels is maximum possible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"24"Someone give a strange birthday present to Ivan. It is hedgehog — connected undirected graph in which one vertex has degree at least $$$3$$$ (we will call it center) and all other vertices has degree 1. Ivan thought that hedgehog is too boring and decided to make himself $$$k$$$-multihedgehog.Let us define $$$k$$$-multihedgehog as follows: $$$1$$$-multihedgehog is hedgehog: it has one vertex of degree at least $$$3$$$ and some vertices of degree 1. For all $$$k \ge 2$$$, $$$k$$$-multihedgehog is $$$(k-1)$$$-multihedgehog in which the following changes has been made for each vertex $$$v$$$ with degree 1: let $$$u$$$ be its only neighbor; remove vertex $$$v$$$, create a new hedgehog with center at vertex $$$w$$$ and connect vertices $$$u$$$ and $$$w$$$ with an edge. New hedgehogs can differ from each other and the initial gift. Thereby $$$k$$$-multihedgehog is a tree. Ivan made $$$k$$$-multihedgehog but he is not sure that he did not make any mistakes. That is why he asked you to check if his tree is indeed $$$k$$$-multihedgehog.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"25"a is an array of n positive integers, all of which are not greater than n.You have to process q queries to this array. Each query is represented by two numbers p and k. Several operations are performed in each query; each operation changes p to p + ap + k. There operations are applied until p becomes greater than n. The answer to the query is the number of performed operations.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"26"After the lessons n groups of schoolchildren went outside and decided to visit Polycarpus to celebrate his birthday. We know that the i-th group consists of si friends (1 ≤ si ≤ 4), and they want to go to Polycarpus together. They decided to get there by taxi. Each car can carry at most four passengers. What minimum number of cars will the children need if all members of each group should ride in the same taxi (but one taxi can take more than one group)?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"27"You are given the following concurrent program. There are N processes and the i-th process has the following pseudocode: repeat ni times    yi := y    y := yi + 1end repeatHere y is a shared variable. Everything else is local for the process. All actions on a given row are atomic, i.e. when the process starts executing a row it is never interrupted. Beyond that all interleavings are possible, i.e. every process that has yet work to do can be granted the rights to execute its next row. In the beginning y = 0. You will be given an integer W and ni, for i = 1, ... , N. Determine if it is possible that after all processes terminate, y = W, and if it is possible output an arbitrary schedule that will produce this final value.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"28"One day Jeff got hold of an integer sequence a1, a2, ..., an of length n. The boy immediately decided to analyze the sequence. For that, he needs to find all values of x, for which these conditions hold:  x occurs in sequence a.  Consider all positions of numbers x in the sequence a (such i, that ai = x). These numbers, sorted in the increasing order, must form an arithmetic progression. Help Jeff, find all x that meet the problem conditions.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"29"Consider an n × m grid. Initially all the cells of the grid are colored white. Lenny has painted some of the cells (at least one) black. We call a painted grid convex if one can walk from any black cell to any another black cell using a path of side-adjacent black cells changing his direction at most once during the path. In the figure below, the left grid is convex while the right one is not convex, because there exist two cells which need more than one time to change direction in their path.  You're given a painted grid in the input. Tell Lenny if the grid is convex or not.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"30"You are given a matrix $$$a$$$ of size $$$n \times m$$$ consisting of integers.You can choose no more than $$$\left\lfloor\frac{m}{2}\right\rfloor$$$ elements in each row. Your task is to choose these elements in such a way that their sum is divisible by $$$k$$$ and this sum is the maximum.In other words, you can choose no more than a half (rounded down) of elements in each row, you have to find the maximum sum of these elements divisible by $$$k$$$.Note that you can choose zero elements (and the sum of such set is $$$0$$$).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"31"Nastya received one more array on her birthday, this array can be used to play a traditional Byteland game on it. However, to play the game the players should first select such a subsegment of the array that , where p is the product of all integers on the given array, s is their sum, and k is a given constant for all subsegments. Nastya wonders how many subsegments of the array fit the described conditions. A subsegment of an array is several consecutive integers of the array.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"32"There are $$$n$$$ astronauts working on some space station. An astronaut with the number $$$i$$$ ($$$1 \le i \le n$$$) has power $$$a_i$$$.An evil humanoid has made his way to this space station. The power of this humanoid is equal to $$$h$$$. Also, the humanoid took with him two green serums and one blue serum.In one second , a humanoid can do any of three actions:  to absorb an astronaut with power strictly less humanoid power;  to use green serum, if there is still one left;  to use blue serum, if there is still one left. When an astronaut with power $$$a_i$$$ is absorbed, this astronaut disappears, and power of the humanoid increases by $$$\lfloor \frac{a_i}{2} \rfloor$$$, that is, an integer part of $$$\frac{a_i}{2}$$$. For example, if a humanoid absorbs an astronaut with power $$$4$$$, its power increases by $$$2$$$, and if a humanoid absorbs an astronaut with power $$$7$$$, its power increases by $$$3$$$.After using the green serum, this serum disappears, and the power of the humanoid doubles, so it increases by $$$2$$$ times.After using the blue serum, this serum disappears, and the power of the humanoid triples, so it increases by $$$3$$$ times.The humanoid is wondering what the maximum number of astronauts he will be able to absorb if he acts optimally.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"33"Let's call an undirected graph of n vertices p-interesting, if the following conditions fulfill:   the graph contains exactly 2n + p edges;  the graph doesn't contain self-loops and multiple edges;  for any integer k (1 ≤ k ≤ n), any subgraph consisting of k vertices contains at most 2k + p edges. A subgraph of a graph is some set of the graph vertices and some set of the graph edges. At that, the set of edges must meet the condition: both ends of each edge from the set must belong to the chosen set of vertices. Your task is to find a p-interesting graph consisting of n vertices.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"34Let's call the roundness of the number the number of zeros to which it ends.You have an array of n numbers. You need to choose a subset of exactly k numbers so that the roundness of the product of the selected numbers will be maximum possible.,['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"35"Polycarp analyzes the prices of the new berPhone. At his disposal are the prices for $$$n$$$ last days: $$$a_1, a_2, \dots, a_n$$$, where $$$a_i$$$ is the price of berPhone on the day $$$i$$$.Polycarp considers the price on the day $$$i$$$ to be bad if later (that is, a day with a greater number) berPhone was sold at a lower price. For example, if $$$n=6$$$ and $$$a=[3, 9, 4, 6, 7, 5]$$$, then the number of days with a bad price is $$$3$$$ — these are days $$$2$$$ ($$$a_2=9$$$), $$$4$$$ ($$$a_4=6$$$) and $$$5$$$ ($$$a_5=7$$$).Print the number of days with a bad price.You have to answer $$$t$$$ independent data sets.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"36"You are given an undirected connected graph consisting of n vertices and m edges. There are no loops and no multiple edges in the graph.You are also given two distinct vertices s and t, and two values ds and dt. Your task is to build any spanning tree of the given graph (note that the graph is not weighted), such that the degree of the vertex s doesn't exceed ds, and the degree of the vertex t doesn't exceed dt, or determine, that there is no such spanning tree.The spanning tree of the graph G is a subgraph which is a tree and contains all vertices of the graph G. In other words, it is a connected graph which contains n - 1 edges and can be obtained by removing some of the edges from G.The degree of a vertex is the number of edges incident to this vertex.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"37"Limak is a little bear who loves to play. Today he is playing by destroying block towers. He built n towers in a row. The i-th tower is made of hi identical blocks. For clarification see picture for the first sample.Limak will repeat the following operation till everything is destroyed.Block is called internal if it has all four neighbors, i.e. it has each side (top, left, down and right) adjacent to other block or to the floor. Otherwise, block is boundary. In one operation Limak destroys all boundary blocks. His paws are very fast and he destroys all those blocks at the same time.Limak is ready to start. You task is to count how many operations will it take him to destroy all towers.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"38"Consider a sequence [a1, a2, ... , an]. Define its prefix product sequence .Now given n, find a permutation of [1, 2, ..., n], such that its prefix product sequence is a permutation of [0, 1, ..., n - 1].","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"39"The capital of Berland has n multifloor buildings. The architect who built up the capital was very creative, so all the houses were built in one row.Let's enumerate all the houses from left to right, starting with one. A house is considered to be luxurious if the number of floors in it is strictly greater than in all the houses with larger numbers. In other words, a house is luxurious if the number of floors in it is strictly greater than in all the houses, which are located to the right from it. In this task it is assumed that the heights of floors in the houses are the same.The new architect is interested in n questions, i-th of them is about the following: ""how many floors should be added to the i-th house to make it luxurious?"" (for all i from 1 to n, inclusive). You need to help him cope with this task.Note that all these questions are independent from each other — the answer to the question for house i does not affect other answers (i.e., the floors to the houses are not actually added).",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"40"Polycarp started working at a bank. He was assigned to monitor the ATM. The ATM initially contains $$$s$$$ rubles.A queue of $$$n$$$ students lined up to him. Each student wants to either withdraw a certain amount of money or deposit it into an account. If $$$a_i$$$ is positive, then the student credits that amount of money via ATM. Otherwise, the student withdraws $$$|a_i|$$$ rubles.In the beginning, the ATM is turned off and an arbitrary number of students are not served. At some point, Polycarp turns on the ATM, which has an initial amount of $$$s$$$ rubles. Then, the remaining students start queueing at the ATM. If at some point in time there is less money in the ATM than the student wants to withdraw, then the student is not served and Polycarp turns off the ATM and does not turn it on anymore.More formally, the students that are served are forming a contiguous subsequence.Polycarp wants the ATM to serve the maximum number of students. Help him in this matter. Print the numbers of the first and last student, or determine that he will not be able to serve anyone.In other words, find such a longest continuous segment of students that, starting with the sum of $$$s$$$ at the ATM, all these students will be served. ATM serves students consistently (i.e. one after another in the order of the queue).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"41"Pavel cooks barbecue. There are n skewers, they lay on a brazier in a row, each on one of n positions. Pavel wants each skewer to be cooked some time in every of n positions in two directions: in the one it was directed originally and in the reversed direction.Pavel has a plan: a permutation p and a sequence b1, b2, ..., bn, consisting of zeros and ones. Each second Pavel move skewer on position i to position pi, and if bi equals 1 then he reverses it. So he hope that every skewer will visit every position in both directions.Unfortunately, not every pair of permutation p and sequence b suits Pavel. What is the minimum total number of elements in the given permutation p and the given sequence b he needs to change so that every skewer will visit each of 2n placements? Note that after changing the permutation should remain a permutation as well.There is no problem for Pavel, if some skewer visits some of the placements several times before he ends to cook. In other words, a permutation p and a sequence b suit him if there is an integer k (k ≥ 2n), so that after k seconds each skewer visits each of the 2n placements.It can be shown that some suitable pair of permutation p and sequence b exists for any n.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"42"As you very well know, the whole Universe traditionally uses three-dimensional Cartesian system of coordinates. In this system each point corresponds to three real coordinates (x, y, z). In this coordinate system, the distance between the center of the Universe and the point is calculated by the following formula: . Mushroom scientists that work for the Great Mushroom King think that the Universe isn't exactly right and the distance from the center of the Universe to a point equals xa·yb·zc.To test the metric of mushroom scientists, the usual scientists offered them a task: find such x, y, z (0 ≤ x, y, z; x + y + z ≤ S), that the distance between the center of the Universe and the point (x, y, z) is maximum possible in the metric of mushroom scientists. The mushroom scientists aren't good at maths, so they commissioned you to do the task.Note that in this problem, it is considered that 00 = 1.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"43"Pay attention: this problem is interactive.Penguin Xoriy came up with a new game recently. He has n icicles numbered from 1 to n. Each icicle has a temperature — an integer from 1 to 109. Exactly two of these icicles are special: their temperature is y, while a temperature of all the others is x ≠ y. You have to find those special icicles. You can choose a non-empty subset of icicles and ask the penguin what is the bitwise exclusive OR (XOR) of the temperatures of the icicles in this subset. Note that you can't ask more than 19 questions.You are to find the special icicles.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"44"You got a box with a combination lock. The lock has a display showing n digits. There are two buttons on the box, each button changes digits on the display. You have quickly discovered that the first button adds 1 to all the digits (all digits 9 become digits 0), and the second button shifts all the digits on the display one position to the right (the last digit becomes the first one). For example, if the display is currently showing number 579, then if we push the first button, the display will show 680, and if after that we push the second button, the display will show 068.You know that the lock will open if the display is showing the smallest possible number that can be obtained by pushing the buttons in some order. The leading zeros are ignored while comparing numbers. Now your task is to find the desired number.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"45"There is a square field of size $$$n \times n$$$ in which two cells are marked. These cells can be in the same row or column.You are to mark two more cells so that they are the corners of a rectangle with sides parallel to the coordinate axes.For example, if $$$n=4$$$ and a rectangular field looks like this (there are asterisks in the marked cells):$$$$$$ \begin{matrix} . & . & * & . \\ . & . & . & . \\ * & . & . & . \\ . & . & . & . \\ \end{matrix} $$$$$$Then you can mark two more cells as follows$$$$$$ \begin{matrix} * & . & * & . \\ . & . & . & . \\ * & . & * & . \\ . & . & . & . \\ \end{matrix} $$$$$$If there are several possible solutions, then print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"46"Polycarp wants to cook a soup. To do it, he needs to buy exactly $$$n$$$ liters of water.There are only two types of water bottles in the nearby shop — $$$1$$$-liter bottles and $$$2$$$-liter bottles. There are infinitely many bottles of these two types in the shop.The bottle of the first type costs $$$a$$$ burles and the bottle of the second type costs $$$b$$$ burles correspondingly.Polycarp wants to spend as few money as possible. Your task is to find the minimum amount of money (in burles) Polycarp needs to buy exactly $$$n$$$ liters of water in the nearby shop if the bottle of the first type costs $$$a$$$ burles and the bottle of the second type costs $$$b$$$ burles. You also have to answer $$$q$$$ independent queries.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"47"You are given the strings $$$a$$$ and $$$b$$$, consisting of lowercase Latin letters. You can do any number of the following operations in any order:   if $$$|a| > 0$$$ (the length of the string $$$a$$$ is greater than zero), delete the first character of the string $$$a$$$, that is, replace $$$a$$$ with $$$a_2 a_3 \ldots a_n$$$;  if $$$|a| > 0$$$, delete the last character of the string $$$a$$$, that is, replace $$$a$$$ with $$$a_1 a_2 \ldots a_{n-1}$$$;  if $$$|b| > 0$$$ (the length of the string $$$b$$$ is greater than zero), delete the first character of the string $$$b$$$, that is, replace $$$b$$$ with $$$b_2 b_3 \ldots b_n$$$;  if $$$|b| > 0$$$, delete the last character of the string $$$b$$$, that is, replace $$$b$$$ with $$$b_1 b_2 \ldots b_{n-1}$$$. Note that after each of the operations, the string $$$a$$$ or $$$b$$$ may become empty.For example, if $$$a=$$$""hello"" and $$$b=$$$""icpc"", then you can apply the following sequence of operations:   delete the first character of the string $$$a$$$ $$$\Rightarrow$$$ $$$a=$$$""ello"" and $$$b=$$$""icpc"";  delete the first character of the string $$$b$$$ $$$\Rightarrow$$$ $$$a=$$$""ello"" and $$$b=$$$""cpc"";  delete the first character of the string $$$b$$$ $$$\Rightarrow$$$ $$$a=$$$""ello"" and $$$b=$$$""pc"";  delete the last character of the string $$$a$$$ $$$\Rightarrow$$$ $$$a=$$$""ell"" and $$$b=$$$""pc"";  delete the last character of the string $$$b$$$ $$$\Rightarrow$$$ $$$a=$$$""ell"" and $$$b=$$$""p"". For the given strings $$$a$$$ and $$$b$$$, find the minimum number of operations for which you can make the strings $$$a$$$ and $$$b$$$ equal. Note that empty strings are also equal.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"48"Alice lives on a flat planet that can be modeled as a square grid of size $$$n \times n$$$, with rows and columns enumerated from $$$1$$$ to $$$n$$$. We represent the cell at the intersection of row $$$r$$$ and column $$$c$$$ with ordered pair $$$(r, c)$$$. Each cell in the grid is either land or water.  An example planet with $$$n = 5$$$. It also appears in the first sample test. Alice resides in land cell $$$(r_1, c_1)$$$. She wishes to travel to land cell $$$(r_2, c_2)$$$. At any moment, she may move to one of the cells adjacent to where she is—in one of the four directions (i.e., up, down, left, or right).Unfortunately, Alice cannot swim, and there is no viable transportation means other than by foot (i.e., she can walk only on land). As a result, Alice's trip may be impossible.To help Alice, you plan to create at most one tunnel between some two land cells. The tunnel will allow Alice to freely travel between the two endpoints. Indeed, creating a tunnel is a lot of effort: the cost of creating a tunnel between cells $$$(r_s, c_s)$$$ and $$$(r_t, c_t)$$$ is $$$(r_s-r_t)^2 + (c_s-c_t)^2$$$.For now, your task is to find the minimum possible cost of creating at most one tunnel so that Alice could travel from $$$(r_1, c_1)$$$ to $$$(r_2, c_2)$$$. If no tunnel needs to be created, the cost is $$$0$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"49"Caisa is now at home and his son has a simple task for him.Given a rooted tree with n vertices, numbered from 1 to n (vertex 1 is the root). Each vertex of the tree has a value. You should answer q queries. Each query is one of the following:  Format of the query is ""1 v"". Let's write out the sequence of vertices along the path from the root to vertex v: u1, u2, ..., uk (u1 = 1; uk = v). You need to output such a vertex ui that gcd(value of ui, value of v) > 1 and i < k. If there are several possible vertices ui pick the one with maximum value of i. If there is no such vertex output -1.  Format of the query is ""2 v w"". You must change the value of vertex v to w. You are given all the queries, help Caisa to solve the problem.","['math', 'number theory', 'trees']","[0, 0, 0, 1, 1, 0, 0, 1]"50"One unknown hacker wants to get the admin's password of AtForces testing system, to get problems from the next contest. To achieve that, he sneaked into the administrator's office and stole a piece of paper with a list of $$$n$$$ passwords — strings, consists of small Latin letters.Hacker went home and started preparing to hack AtForces. He found that the system contains only passwords from the stolen list and that the system determines the equivalence of the passwords $$$a$$$ and $$$b$$$ as follows:  two passwords $$$a$$$ and $$$b$$$ are equivalent if there is a letter, that exists in both $$$a$$$ and $$$b$$$;  two passwords $$$a$$$ and $$$b$$$ are equivalent if there is a password $$$c$$$ from the list, which is equivalent to both $$$a$$$ and $$$b$$$. If a password is set in the system and an equivalent one is applied to access the system, then the user is accessed into the system.For example, if the list contain passwords ""a"", ""b"", ""ab"", ""d"", then passwords ""a"", ""b"", ""ab"" are equivalent to each other, but the password ""d"" is not equivalent to any other password from list. In other words, if:  admin's password is ""b"", then you can access to system by using any of this passwords: ""a"", ""b"", ""ab"";  admin's password is ""d"", then you can access to system by using only ""d"". Only one password from the list is the admin's password from the testing system. Help hacker to calculate the minimal number of passwords, required to guaranteed access to the system. Keep in mind that the hacker does not know which password is set in the system.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"51"You are given an array a consisting of n positive integers. You pick two integer numbers l and r from 1 to n, inclusive (numbers are picked randomly, equiprobably and independently). If l > r, then you swap values of l and r. You have to calculate the expected value of the number of unique elements in segment of the array from index l to index r, inclusive (1-indexed).","['math', 'probabilities']","[0, 0, 0, 1, 0, 1, 0, 0]"52"Parsa has a humongous tree on $$$n$$$ vertices.On each vertex $$$v$$$ he has written two integers $$$l_v$$$ and $$$r_v$$$.To make Parsa's tree look even more majestic, Nima wants to assign a number $$$a_v$$$ ($$$l_v \le a_v \le r_v$$$) to each vertex $$$v$$$ such that the beauty of Parsa's tree is maximized.Nima's sense of the beauty is rather bizarre. He defines the beauty of the tree as the sum of $$$|a_u - a_v|$$$ over all edges $$$(u, v)$$$ of the tree.Since Parsa's tree is too large, Nima can't maximize its beauty on his own. Your task is to find the maximum possible beauty for Parsa's tree.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"53"A basketball competition is held where the number of players in a team does not have a maximum or minimum limit (not necessarily $$$5$$$ players in one team for each match). There are $$$N$$$ candidate players in the competition that will be trained by Pak Chanek, the best basketball coach on earth. The $$$i$$$-th candidate player has a power of $$$P_i$$$.Pak Chanek will form zero or more teams from the $$$N$$$ candidate players on the condition that each candidate player may only join in at most one team. Each of Pak Chanek's teams will be sent to compete once with an enemy team that has a power of $$$D$$$. In each match, the team sent is said to defeat the enemy team if the sum of powers from the formed players is strictly greater than $$$D$$$.One of Pak Chanek's skills is that when a team that has been formed plays in a match, he can change the power of each player in the team to be equal to the biggest player power from the team.Determine the maximum number of wins that can be achieved by Pak Chanek.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"54"$$$n$$$ students attended the first meeting of the Berland SU programming course ($$$n$$$ is even). All students will be divided into two groups. Each group will be attending exactly one lesson each week during one of the five working days (Monday, Tuesday, Wednesday, Thursday and Friday), and the days chosen for the groups must be different. Furthermore, both groups should contain the same number of students.Each student has filled a survey in which they told which days of the week are convenient for them to attend a lesson, and which are not. Your task is to determine if it is possible to choose two different week days to schedule the lessons for the group (the first group will attend the lesson on the first chosen day, the second group will attend the lesson on the second chosen day), and divide the students into two groups, so the groups have equal sizes, and for each student, the chosen lesson day for their group is convenient.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"55"Sereja has a bracket sequence s1, s2, ..., sn, or, in other words, a string s of length n, consisting of characters ""("" and "")"".Sereja needs to answer m queries, each of them is described by two integers li, ri (1 ≤ li ≤ ri ≤ n). The answer to the i-th query is the length of the maximum correct bracket subsequence of sequence sli, sli + 1, ..., sri. Help Sereja answer all queries.You can find the definitions for a subsequence and a correct bracket sequence in the notes.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"56You are given a matrix f with 4 rows and n columns. Each element of the matrix is either an asterisk (*) or a dot (.).You may perform the following operation arbitrary number of times: choose a square submatrix of f with size k × k (where 1 ≤ k ≤ 4) and replace each element of the chosen submatrix with a dot. Choosing a submatrix of size k × k costs ak coins.What is the minimum number of coins you have to pay to replace all asterisks with dots?,[],"[0, 0, 0, 0, 0, 0, 0, 0]"57"You are given a string, consisting of lowercase Latin letters.A pair of neighbouring letters in a string is considered ugly if these letters are also neighbouring in a alphabet. For example, string ""abaca"" contains ugly pairs at positions $$$(1, 2)$$$ — ""ab"" and $$$(2, 3)$$$ — ""ba"". Letters 'a' and 'z' aren't considered neighbouring in a alphabet.Can you rearrange the letters of a given string so that there are no ugly pairs? You can choose any order of the letters of the given string but you can't add any new letters or remove the existing ones. You can also leave the order the same.If there are multiple answers, print any of them.You also have to answer $$$T$$$ separate queries.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"58"You are given an integer $$$n$$$ and an integer $$$k$$$.In one step you can do one of the following moves:   decrease $$$n$$$ by $$$1$$$;  divide $$$n$$$ by $$$k$$$ if $$$n$$$ is divisible by $$$k$$$. For example, if $$$n = 27$$$ and $$$k = 3$$$ you can do the following steps: $$$27 \rightarrow 26 \rightarrow 25 \rightarrow 24 \rightarrow 8 \rightarrow 7 \rightarrow 6 \rightarrow 2 \rightarrow 1 \rightarrow 0$$$.You are asked to calculate the minimum number of steps to reach $$$0$$$ from $$$n$$$. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"59"By the age of three Smart Beaver mastered all arithmetic operations and got this summer homework from the amazed teacher:You are given a sequence of integers a1, a2, ..., an. Your task is to perform on it m consecutive operations of the following type:  For given numbers xi and vi assign value vi to element axi.  For given numbers li and ri you've got to calculate sum , where f0 = f1 = 1 and at i ≥ 2: fi = fi - 1 + fi - 2.  For a group of three numbers li ri di you should increase value ax by di for all x (li ≤ x ≤ ri). Smart Beaver planned a tour around great Canadian lakes, so he asked you to help him solve the given problem.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"60"Once again, Boris needs the help of Anton in creating a task. This time Anton needs to solve the following problem:There are two arrays of integers $$$a$$$ and $$$b$$$ of length $$$n$$$. It turned out that array $$$a$$$ contains only elements from the set $$$\{-1, 0, 1\}$$$.Anton can perform the following sequence of operations any number of times:   Choose any pair of indexes $$$(i, j)$$$ such that $$$1 \le i < j \le n$$$. It is possible to choose the same pair $$$(i, j)$$$ more than once.   Add $$$a_i$$$ to $$$a_j$$$. In other words, $$$j$$$-th element of the array becomes equal to $$$a_i + a_j$$$. For example, if you are given array $$$[1, -1, 0]$$$, you can transform it only to $$$[1, -1, -1]$$$, $$$[1, 0, 0]$$$ and $$$[1, -1, 1]$$$ by one operation.Anton wants to predict if it is possible to apply some number (zero or more) of these operations to the array $$$a$$$ so that it becomes equal to array $$$b$$$. Can you help him?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"61"Two integer sequences existed initially — one of them was strictly increasing, and the other one — strictly decreasing.Strictly increasing sequence is a sequence of integers $$$[x_1 < x_2 < \dots < x_k]$$$. And strictly decreasing sequence is a sequence of integers $$$[y_1 > y_2 > \dots > y_l]$$$. Note that the empty sequence and the sequence consisting of one element can be considered as increasing or decreasing.They were merged into one sequence $$$a$$$. After that sequence $$$a$$$ got shuffled. For example, some of the possible resulting sequences $$$a$$$ for an increasing sequence $$$[1, 3, 4]$$$ and a decreasing sequence $$$[10, 4, 2]$$$ are sequences $$$[1, 2, 3, 4, 4, 10]$$$ or $$$[4, 2, 1, 10, 4, 3]$$$.This shuffled sequence $$$a$$$ is given in the input.Your task is to find any two suitable initial sequences. One of them should be strictly increasing and the other one — strictly decreasing. Note that the empty sequence and the sequence consisting of one element can be considered as increasing or decreasing.If there is a contradiction in the input and it is impossible to split the given sequence $$$a$$$ to increasing and decreasing sequences, print ""NO"".",[],"[0, 0, 0, 0, 0, 0, 0, 0]"62"Andrew loves the sea. That's why, at the height of the summer season, he decided to go to the beach, taking a sunbed with him to sunbathe.The beach is a rectangular field with $$$n$$$ rows and $$$m$$$ columns. Some cells of the beach are free, some have roads, stones, shops and other non-movable objects. Some of two adjacent along the side cells can have sunbeds located either horizontally or vertically.Andrew hopes to put his sunbed somewhere, but that's a bad luck, there may no longer be free places for him! That's why Andrew asked you to help him to find a free place for his sunbed. Andrew's sunbed also should be places on two adjacent cells. If there are no two adjacent free cells, then in order to free some place for a sunbed, you will have to disturb other tourists. You can do the following actions:  Come to some sunbed and, after causing $$$p$$$ units of discomfort to its owner, lift the sunbed by one of its sides and rotate it by $$$90$$$ degrees. One half of the sunbed must remain in the same cell and another half of the sunbed must move to the free cell. At the same time, anything could be on the way of a sunbed during the rotation .   Rotation of the sunbed by $$$90$$$ degrees around cell $$$(1, 2)$$$.  Come to some sunbed and, after causing $$$q$$$ units of discomfort to its owner, shift the sunbed along its long side by one cell. One half of the sunbed must move to the place of another, and another — to the free cell.   Shift of the sunbed by one cell to the right. In any moment each sunbed occupies two adjacent free cells. You cannot move more than one sunbed at a time.Help Andrew to free a space for his sunbed, causing the minimum possible number of units of discomfort to other tourists, or detect that it is impossible.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"63"You are given the array $$$a$$$ consisting of $$$n$$$ positive (greater than zero) integers.In one move, you can choose two indices $$$i$$$ and $$$j$$$ ($$$i \ne j$$$) such that the absolute difference between $$$a_i$$$ and $$$a_j$$$ is no more than one ($$$|a_i - a_j| \le 1$$$) and remove the smallest of these two elements. If two elements are equal, you can remove any of them (but exactly one).Your task is to find if it is possible to obtain the array consisting of only one element using several (possibly, zero) such moves or not.You have to answer $$$t$$$ independent test cases.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"64"This is the hard version of the problem. The only difference is that in this version $$$n \leq 200000$$$. You can make hacks only if both versions of the problem are solved.There are $$$n$$$ potions in a line, with potion $$$1$$$ on the far left and potion $$$n$$$ on the far right. Each potion will increase your health by $$$a_i$$$ when drunk. $$$a_i$$$ can be negative, meaning that potion will decrease will health.You start with $$$0$$$ health and you will walk from left to right, from first potion to the last one. At each potion, you may choose to drink it or ignore it. You must ensure that your health is always non-negative.What is the largest number of potions you can drink?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"65"Note that the memory limit is unusual.You are given a multiset consisting of $$$n$$$ integers. You have to process queries of two types:  add integer $$$k$$$ into the multiset;  find the $$$k$$$-th order statistics in the multiset and remove it. $$$k$$$-th order statistics in the multiset is the $$$k$$$-th element in the sorted list of all elements of the multiset. For example, if the multiset contains elements $$$1$$$, $$$4$$$, $$$2$$$, $$$1$$$, $$$4$$$, $$$5$$$, $$$7$$$, and $$$k = 3$$$, then you have to find the $$$3$$$-rd element in $$$[1, 1, 2, 4, 4, 5, 7]$$$, which is $$$2$$$. If you try to delete an element which occurs multiple times in the multiset, only one occurence is removed. After processing all queries, print any number belonging to the multiset, or say that it is empty.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"66"Today we will be playing a red and white colouring game (no, this is not the Russian Civil War; these are just the colours of the Canadian flag).You are given an $$$n \times m$$$ grid of ""R"", ""W"", and ""."" characters. ""R"" is red, ""W"" is white and ""."" is blank. The neighbours of a cell are those that share an edge with it (those that only share a corner do not count).Your job is to colour the blank cells red or white so that every red cell only has white neighbours (and no red ones) and every white cell only has red neighbours (and no white ones). You are not allowed to recolour already coloured cells.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"67"Note that the memory limit in this problem is lower than in others.You have a vertical strip with $$$n$$$ cells, numbered consecutively from $$$1$$$ to $$$n$$$ from top to bottom.You also have a token that is initially placed in cell $$$n$$$. You will move the token up until it arrives at cell $$$1$$$.Let the token be in cell $$$x > 1$$$ at some moment. One shift of the token can have either of the following kinds:   Subtraction: you choose an integer $$$y$$$ between $$$1$$$ and $$$x-1$$$, inclusive, and move the token from cell $$$x$$$ to cell $$$x - y$$$.  Floored division: you choose an integer $$$z$$$ between $$$2$$$ and $$$x$$$, inclusive, and move the token from cell $$$x$$$ to cell $$$\lfloor \frac{x}{z} \rfloor$$$ ($$$x$$$ divided by $$$z$$$ rounded down). Find the number of ways to move the token from cell $$$n$$$ to cell $$$1$$$ using one or more shifts, and print it modulo $$$m$$$. Note that if there are several ways to move the token from one cell to another in one shift, all these ways are considered distinct (check example explanation for a better understanding).","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"68"The new camp by widely-known over the country Spring Programming Camp is going to start soon. Hence, all the team of friendly curators and teachers started composing the camp's schedule. After some continuous discussion, they came up with a schedule $$$s$$$, which can be represented as a binary string, in which the $$$i$$$-th symbol is '1' if students will write the contest in the $$$i$$$-th day and '0' if they will have a day off.At the last moment Gleb said that the camp will be the most productive if it runs with the schedule $$$t$$$ (which can be described in the same format as schedule $$$s$$$). Since the number of days in the current may be different from number of days in schedule $$$t$$$, Gleb required that the camp's schedule must be altered so that the number of occurrences of $$$t$$$ in it as a substring is maximum possible. At the same time, the number of contest days and days off shouldn't change, only their order may change.Could you rearrange the schedule in the best possible way?",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"69"Diana loves playing with numbers. She's got $$$n$$$ cards with positive integer numbers $$$a_i$$$ written on them. She spends her free time multiplying the numbers on the cards. She picks a non-empty subset of the cards and multiplies all the numbers $$$a_i$$$ written on them.Diana is happy when the product of the numbers ends with her favorite digit $$$d$$$. Now she is curious what cards she should pick so that the product of the numbers on them is the largest possible and the last decimal digit of the product is $$$d$$$. Please, help her.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"70"You are given an unweighted tree with n vertices. Then n - 1 following operations are applied to the tree. A single operation consists of the following steps:   choose two leaves;  add the length of the simple path between them to the answer;  remove one of the chosen leaves from the tree. Initial answer (before applying operations) is 0. Obviously after n - 1 such operations the tree will consist of a single vertex. Calculate the maximal possible answer you can achieve, and construct a sequence of operations that allows you to achieve this answer!","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"71" Frodo was caught by Saruman. He tore a pouch from Frodo's neck, shook out its contents —there was a pile of different rings: gold and silver...""How am I to tell which is the One?!"" the mage howled.""Throw them one by one into the Cracks of Doom and watch when Mordor falls!"" Somewhere in a parallel Middle-earth, when Saruman caught Frodo, he only found $$$n$$$ rings. And the $$$i$$$-th ring was either gold or silver. For convenience Saruman wrote down a binary string $$$s$$$ of $$$n$$$ characters, where the $$$i$$$-th character was 0 if the $$$i$$$-th ring was gold, and 1 if it was silver.Saruman has a magic function $$$f$$$, which takes a binary string and returns a number obtained by converting the string into a binary number and then converting the binary number into a decimal number. For example, $$$f(001010) = 10, f(111) = 7, f(11011101) = 221$$$.Saruman, however, thinks that the order of the rings plays some important role. He wants to find $$$2$$$ pairs of integers $$$(l_1, r_1), (l_2, r_2)$$$, such that: $$$1 \le l_1 \le n$$$, $$$1 \le r_1 \le n$$$, $$$r_1-l_1+1\ge \lfloor \frac{n}{2} \rfloor$$$  $$$1 \le l_2 \le n$$$, $$$1 \le r_2 \le n$$$, $$$r_2-l_2+1\ge \lfloor \frac{n}{2} \rfloor$$$  Pairs $$$(l_1, r_1)$$$ and $$$(l_2, r_2)$$$ are distinct. That is, at least one of $$$l_1 \neq l_2$$$ and $$$r_1 \neq r_2$$$ must hold. Let $$$t$$$ be the substring $$$s[l_1:r_1]$$$ of $$$s$$$, and $$$w$$$ be the substring $$$s[l_2:r_2]$$$ of $$$s$$$. Then there exists non-negative integer $$$k$$$, such that $$$f(t) = f(w) \cdot k$$$.Here substring $$$s[l:r]$$$ denotes $$$s_ls_{l+1}\ldots s_{r-1}s_r$$$, and $$$\lfloor x \rfloor$$$ denotes rounding the number down to the nearest integer.Help Saruman solve this problem! It is guaranteed that under the constraints of the problem at least one solution exists.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"72"The Kingdom of Kremland is a tree (a connected undirected graph without cycles) consisting of $$$n$$$ vertices. Each vertex $$$i$$$ has its own value $$$a_i$$$. All vertices are connected in series by edges. Formally, for every $$$1 \leq i < n$$$ there is an edge between the vertices of $$$i$$$ and $$$i+1$$$.Denote the function $$$f(l, r)$$$, which takes two integers $$$l$$$ and $$$r$$$ ($$$l \leq r$$$):    We leave in the tree only vertices whose values ​​range from $$$l$$$ to $$$r$$$.    The value of the function will be the number of connected components in the new graph. Your task is to calculate the following sum: $$$$$$\sum_{l=1}^{n} \sum_{r=l}^{n} f(l, r) $$$$$$",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"73"Treeland is a country in which there are n towns connected by n - 1 two-way road such that it's possible to get from any town to any other town. In Treeland there are 2k universities which are located in different towns. Recently, the president signed the decree to connect universities by high-speed network.The Ministry of Education understood the decree in its own way and decided that it was enough to connect each university with another one by using a cable. Formally, the decree will be done! To have the maximum sum in the budget, the Ministry decided to divide universities into pairs so that the total length of the required cable will be maximum. In other words, the total distance between universities in k pairs should be as large as possible. Help the Ministry to find the maximum total distance. Of course, each university should be present in only one pair. Consider that all roads have the same length which is equal to 1. ","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"74"Vasya has become interested in wrestling. In wrestling wrestlers use techniques for which they are awarded points by judges. The wrestler who gets the most points wins.When the numbers of points of both wrestlers are equal, the wrestler whose sequence of points is lexicographically greater, wins.If the sequences of the awarded points coincide, the wrestler who performed the last technique wins. Your task is to determine which wrestler won.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"75"This is an interactive problem.There exists a matrix $$$a$$$ of size $$$n \times m$$$ ($$$n$$$ rows and $$$m$$$ columns), you know only numbers $$$n$$$ and $$$m$$$. The rows of the matrix are numbered from $$$1$$$ to $$$n$$$ from top to bottom, and columns of the matrix are numbered from $$$1$$$ to $$$m$$$ from left to right. The cell on the intersection of the $$$x$$$-th row and the $$$y$$$-th column is denoted as $$$(x, y)$$$.You are asked to find the number of pairs $$$(r, c)$$$ ($$$1 \le r \le n$$$, $$$1 \le c \le m$$$, $$$r$$$ is a divisor of $$$n$$$, $$$c$$$ is a divisor of $$$m$$$) such that if we split the matrix into rectangles of size $$$r \times c$$$ (of height $$$r$$$ rows and of width $$$c$$$ columns, each cell belongs to exactly one rectangle), all those rectangles are pairwise equal.You can use queries of the following type:   ? $$$h$$$ $$$w$$$ $$$i_1$$$ $$$j_1$$$ $$$i_2$$$ $$$j_2$$$ ($$$1 \le h \le n$$$, $$$1 \le w \le m$$$, $$$1 \le i_1, i_2 \le n$$$, $$$1 \le j_1, j_2 \le m$$$) — to check if non-overlapping subrectangles of height $$$h$$$ rows and of width $$$w$$$ columns of matrix $$$a$$$ are equal or not. The upper left corner of the first rectangle is $$$(i_1, j_1)$$$. The upper left corner of the second rectangle is $$$(i_2, j_2)$$$. Subrectangles overlap, if they have at least one mutual cell. If the subrectangles in your query have incorrect coordinates (for example, they go beyond the boundaries of the matrix) or overlap, your solution will be considered incorrect. You can use at most $$$ 3 \cdot \left \lfloor{ \log_2{(n+m)} } \right \rfloor$$$ queries. All elements of the matrix $$$a$$$ are fixed before the start of your program and do not depend on your queries.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"76"This is an interactive problem!Nastia has a hidden permutation $$$p$$$ of length $$$n$$$ consisting of integers from $$$1$$$ to $$$n$$$. You, for some reason, want to figure out the permutation. To do that, you can give her an integer $$$t$$$ ($$$1 \le t \le 2$$$), two different indices $$$i$$$ and $$$j$$$ ($$$1 \le i, j \le n$$$, $$$i \neq j$$$), and an integer $$$x$$$ ($$$1 \le x \le n - 1$$$). Depending on $$$t$$$, she will answer:   $$$t = 1$$$: $$$\max{(\min{(x, p_i)}, \min{(x + 1, p_j)})}$$$;  $$$t = 2$$$: $$$\min{(\max{(x, p_i)}, \max{(x + 1, p_j)})}$$$. You can ask Nastia at most $$$\lfloor \frac {3 \cdot n} { 2} \rfloor + 30$$$ times. It is guaranteed that she will not change her permutation depending on your queries. Can you guess the permutation?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"77"In Ancient Berland there were n cities and m two-way roads of equal length. The cities are numbered with integers from 1 to n inclusively. According to an ancient superstition, if a traveller visits three cities ai, bi, ci in row, without visiting other cities between them, a great disaster awaits him. Overall there are k such city triplets. Each triplet is ordered, which means that, for example, you are allowed to visit the cities in the following order: ai, ci, bi. Vasya wants to get from the city 1 to the city n and not fulfil the superstition. Find out which minimal number of roads he should take. Also you are required to find one of his possible path routes.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"78"A star is a figure of the following type: an asterisk character '*' in the center of the figure and four rays (to the left, right, top, bottom) of the same positive length. The size of a star is the length of its rays. The size of a star must be a positive number (i.e. rays of length $$$0$$$ are not allowed).Let's consider empty cells are denoted by '.', then the following figures are stars:  The leftmost figure is a star of size $$$1$$$, the middle figure is a star of size $$$2$$$ and the rightmost figure is a star of size $$$3$$$. You are given a rectangular grid of size $$$n \times m$$$ consisting only of asterisks '*' and periods (dots) '.'. Rows are numbered from $$$1$$$ to $$$n$$$, columns are numbered from $$$1$$$ to $$$m$$$. Your task is to draw this grid using any number of stars or find out that it is impossible. Stars can intersect, overlap or even coincide with each other. The number of stars in the output can't exceed $$$n \cdot m$$$. Each star should be completely inside the grid. You can use stars of same and arbitrary sizes.In this problem, you do not need to minimize the number of stars. Just find any way to draw the given grid with at most $$$n \cdot m$$$ stars.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"79"Eshag has an array $$$a$$$ consisting of $$$n$$$ integers.Eshag can perform the following operation any number of times: choose some subsequence of $$$a$$$ and delete every element from it which is strictly larger than $$$AVG$$$, where $$$AVG$$$ is the average of the numbers in the chosen subsequence.For example, if $$$a = [1 , 4 , 3 , 2 , 4]$$$ and Eshag applies the operation to the subsequence containing $$$a_1$$$, $$$a_2$$$, $$$a_4$$$ and $$$a_5$$$, then he will delete those of these $$$4$$$ elements which are larger than $$$\frac{a_1+a_2+a_4+a_5}{4} = \frac{11}{4}$$$, so after the operation, the array $$$a$$$ will become $$$a = [1 , 3 , 2]$$$.Your task is to find the maximum number of elements Eshag can delete from the array $$$a$$$ by applying the operation described above some number (maybe, zero) times.A sequence $$$b$$$ is a subsequence of an array $$$c$$$ if $$$b$$$ can be obtained from $$$c$$$ by deletion of several (possibly, zero or all) elements.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"80"Xenia the horse breeder has n (n > 1) horses that stand in a row. Each horse has its own unique number. Initially, the i-th left horse has number i. That is, the sequence of numbers of horses in a row looks as follows (from left to right): 1, 2, 3, ..., n.Xenia trains horses before the performance. During the practice sessions, she consistently gives them commands. Each command is a pair of numbers l, r (1 ≤ l < r ≤ n). The command l, r means that the horses that are on the l-th, (l + 1)-th, (l + 2)-th, ..., r-th places from the left must be rearranged. The horses that initially stand on the l-th and r-th places will swap. The horses on the (l + 1)-th and (r - 1)-th places will swap. The horses on the (l + 2)-th and (r - 2)-th places will swap and so on. In other words, the horses that were on the segment [l, r] change their order to the reverse one.For example, if Xenia commanded l = 2, r = 5, and the sequence of numbers of horses before the command looked as (2, 1, 3, 4, 5, 6), then after the command the sequence will be (2, 5, 4, 3, 1, 6).We know that during the practice Xenia gave at most three commands of the described form. You have got the final sequence of numbers of horses by the end of the practice. Find what commands Xenia gave during the practice. Note that you do not need to minimize the number of commands in the solution, find any valid sequence of at most three commands.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"81"Bob wants to put a new bargaining table in his office. To do so he measured the office room thoroughly and drew its plan: Bob's office room is a rectangular room n × m meters. Each square meter of the room is either occupied by some furniture, or free. A bargaining table is rectangular, and should be placed so, that its sides are parallel to the office walls. Bob doesn't want to change or rearrange anything, that's why all the squares that will be occupied by the table should be initially free. Bob wants the new table to sit as many people as possible, thus its perimeter should be maximal. Help Bob find out the maximum possible perimeter of a bargaining table for his office.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"82"It's another Start[c]up finals, and that means there is pizza to order for the onsite contestants. There are only 2 types of pizza (obviously not, but let's just pretend for the sake of the problem), and all pizzas contain exactly S slices.It is known that the i-th contestant will eat si slices of pizza, and gain ai happiness for each slice of type 1 pizza they eat, and bi happiness for each slice of type 2 pizza they eat. We can order any number of type 1 and type 2 pizzas, but we want to buy the minimum possible number of pizzas for all of the contestants to be able to eat their required number of slices. Given that restriction, what is the maximum possible total happiness that can be achieved?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"83"You are given a positive integer $$$n$$$ greater or equal to $$$2$$$. For every pair of integers $$$a$$$ and $$$b$$$ ($$$2 \le |a|, |b| \le n$$$), you can transform $$$a$$$ into $$$b$$$ if and only if there exists an integer $$$x$$$ such that $$$1 < |x|$$$ and ($$$a \cdot x = b$$$ or $$$b \cdot x = a$$$), where $$$|x|$$$ denotes the absolute value of $$$x$$$.After such a transformation, your score increases by $$$|x|$$$ points and you are not allowed to transform $$$a$$$ into $$$b$$$ nor $$$b$$$ into $$$a$$$ anymore.Initially, you have a score of $$$0$$$. You can start at any integer and transform it as many times as you like. What is the maximum score you can achieve?","['graphs', 'math']","[0, 0, 1, 1, 0, 0, 0, 0]"84"Let's call an array $$$a$$$ of $$$m$$$ integers $$$a_1, a_2, \ldots, a_m$$$ Decinc if $$$a$$$ can be made increasing by removing a decreasing subsequence (possibly empty) from it. For example, if $$$a = [3, 2, 4, 1, 5]$$$, we can remove the decreasing subsequence $$$[a_1, a_4]$$$ from $$$a$$$ and obtain $$$a = [2, 4, 5]$$$, which is increasing.You are given a permutation $$$p$$$ of numbers from $$$1$$$ to $$$n$$$. Find the number of pairs of integers $$$(l, r)$$$ with $$$1 \le l \le r \le n$$$ such that $$$p[l \ldots r]$$$ (the subarray of $$$p$$$ from $$$l$$$ to $$$r$$$) is a Decinc array. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"85"Young boy Artem tries to paint a picture, and he asks his mother Medina to help him. Medina is very busy, that's why she asked for your help.Artem wants to paint an $$$n \times m$$$ board. Each cell of the board should be colored in white or black. Lets $$$B$$$ be the number of black cells that have at least one white neighbor adjacent by the side. Let $$$W$$$ be the number of white cells that have at least one black neighbor adjacent by the side. A coloring is called good if $$$B = W + 1$$$. The first coloring shown below has $$$B=5$$$ and $$$W=4$$$ (all cells have at least one neighbor with the opposite color). However, the second coloring is not good as it has $$$B=4$$$, $$$W=4$$$ (only the bottom right cell doesn't have a neighbor with the opposite color).  Please, help Medina to find any good coloring. It's guaranteed that under given constraints the solution always exists. If there are several solutions, output any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"86"The Central Company has an office with a sophisticated security system. There are $$$10^6$$$ employees, numbered from $$$1$$$ to $$$10^6$$$.The security system logs entrances and departures. The entrance of the $$$i$$$-th employee is denoted by the integer $$$i$$$, while the departure of the $$$i$$$-th employee is denoted by the integer $$$-i$$$.The company has some strict rules about access to its office:  An employee can enter the office at most once per day.  He obviously can't leave the office if he didn't enter it earlier that day.  In the beginning and at the end of every day, the office is empty (employees can't stay at night). It may also be empty at any moment of the day. Any array of events satisfying these conditions is called a valid day.Some examples of valid or invalid days:  $$$[1, 7, -7, 3, -1, -3]$$$ is a valid day ($$$1$$$ enters, $$$7$$$ enters, $$$7$$$ leaves, $$$3$$$ enters, $$$1$$$ leaves, $$$3$$$ leaves).  $$$[2, -2, 3, -3]$$$ is also a valid day.  $$$[2, 5, -5, 5, -5, -2]$$$ is not a valid day, because $$$5$$$ entered the office twice during the same day.  $$$[-4, 4]$$$ is not a valid day, because $$$4$$$ left the office without being in it.  $$$[4]$$$ is not a valid day, because $$$4$$$ entered the office and didn't leave it before the end of the day. There are $$$n$$$ events $$$a_1, a_2, \ldots, a_n$$$, in the order they occurred. This array corresponds to one or more consecutive days. The system administrator erased the dates of events by mistake, but he didn't change the order of the events.You must partition (to cut) the array $$$a$$$ of events into contiguous subarrays, which must represent non-empty valid days (or say that it's impossible). Each array element should belong to exactly one contiguous subarray of a partition. Each contiguous subarray of a partition should be a valid day.For example, if $$$n=8$$$ and $$$a=[1, -1, 1, 2, -1, -2, 3, -3]$$$ then he can partition it into two contiguous subarrays which are valid days: $$$a = [1, -1~ \boldsymbol{|}~ 1, 2, -1, -2, 3, -3]$$$.Help the administrator to partition the given array $$$a$$$ in the required way or report that it is impossible to do. Find any required partition, you should not minimize or maximize the number of parts.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"87"There is a trampoline park with $$$n$$$ trampolines in a line. The $$$i$$$-th of which has strength $$$S_i$$$.Pekora can jump on trampolines in multiple passes. She starts the pass by jumping on any trampoline of her choice. If at the moment Pekora jumps on trampoline $$$i$$$, the trampoline will launch her to position $$$i + S_i$$$, and $$$S_i$$$ will become equal to $$$\max(S_i-1,1)$$$. In other words, $$$S_i$$$ will decrease by $$$1$$$, except of the case $$$S_i=1$$$, when $$$S_i$$$ will remain equal to $$$1$$$. If there is no trampoline in position $$$i + S_i$$$, then this pass is over. Otherwise, Pekora will continue the pass by jumping from the trampoline at position $$$i + S_i$$$ by the same rule as above.Pekora can't stop jumping during the pass until she lands at the position larger than $$$n$$$ (in which there is no trampoline). Poor Pekora!Pekora is a naughty rabbit and wants to ruin the trampoline park by reducing all $$$S_i$$$ to $$$1$$$. What is the minimum number of passes she needs to reduce all $$$S_i$$$ to $$$1$$$?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"88"Everybody knows that the $$$m$$$-coder Tournament will happen soon. $$$m$$$ schools participate in the tournament, and only one student from each school participates.There are a total of $$$n$$$ students in those schools. Before the tournament, all students put their names and the names of their schools into the Technogoblet of Fire. After that, Technogoblet selects the strongest student from each school to participate. Arkady is a hacker who wants to have $$$k$$$ Chosen Ones selected by the Technogoblet. Unfortunately, not all of them are the strongest in their schools, but Arkady can make up some new school names and replace some names from Technogoblet with those. You can't use each made-up name more than once. In that case, Technogoblet would select the strongest student in those made-up schools too.You know the power of each student and schools they study in. Calculate the minimal number of schools Arkady has to make up so that $$$k$$$ Chosen Ones would be selected by the Technogoblet.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"89"Vitya is studying in the third grade. During the last math lesson all the pupils wrote on arithmetic quiz. Vitya is a clever boy, so he managed to finish all the tasks pretty fast and Oksana Fillipovna gave him a new one, that is much harder.Let's denote a flip operation of an integer as follows: number is considered in decimal notation and then reverted. If there are any leading zeroes afterwards, they are thrown away. For example, if we flip 123 the result is the integer 321, but flipping 130 we obtain 31, and by flipping 31 we come to 13.Oksana Fillipovna picked some number a without leading zeroes, and flipped it to get number ar. Then she summed a and ar, and told Vitya the resulting value n. His goal is to find any valid a.As Oksana Fillipovna picked some small integers as a and ar, Vitya managed to find the answer pretty fast and became interested in finding some general algorithm to deal with this problem. Now, he wants you to write the program that for given n finds any a without leading zeroes, such that a + ar = n or determine that such a doesn't exist.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"90"Your favorite music streaming platform has formed a perfectly balanced playlist exclusively for you. The playlist consists of $$$n$$$ tracks numbered from $$$1$$$ to $$$n$$$. The playlist is automatic and cyclic: whenever track $$$i$$$ finishes playing, track $$$i+1$$$ starts playing automatically; after track $$$n$$$ goes track $$$1$$$.For each track $$$i$$$, you have estimated its coolness $$$a_i$$$. The higher $$$a_i$$$ is, the cooler track $$$i$$$ is.Every morning, you choose a track. The playlist then starts playing from this track in its usual cyclic fashion. At any moment, you remember the maximum coolness $$$x$$$ of already played tracks. Once you hear that a track with coolness strictly less than $$$\frac{x}{2}$$$ (no rounding) starts playing, you turn off the music immediately to keep yourself in a good mood.For each track $$$i$$$, find out how many tracks you will listen to before turning off the music if you start your morning with track $$$i$$$, or determine that you will never turn the music off. Note that if you listen to the same track several times, every time must be counted.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"91"Oh no, on the first exam Madoka got this hard problem:Given integer $$$n$$$ and $$$m$$$ pairs of integers ($$$v_i, u_i$$$). Also there is an array $$$b_1, b_2, \ldots, b_n$$$, initially filled with zeros.Then for each index $$$i$$$, where $$$1 \leq i \leq m$$$, perform either $$$b_{v_i} := b_{v_i} - 1$$$ and $$$b_{u_i} := b_{u_i} + 1$$$, or $$$b_{v_i} := b_{v_i} + 1$$$ and $$$b_{u_i} := b_{u_i} - 1$$$. Note that exactly one of these operations should be performed for every $$$i$$$.Also there is an array $$$s$$$ of length $$$n$$$ consisting of $$$0$$$ and $$$1$$$. And there is an array $$$a_1, a_2, \ldots, a_n$$$, where it is guaranteed, that if $$$s_i = 0$$$ holds, then $$$a_i = 0$$$.Help Madoka and determine whenever it is possible to perform operations in such way that for every $$$i$$$, where $$$s_i = 1$$$ it holds that $$$a_i = b_i$$$. If it possible you should also provide Madoka with a way to perform operations.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"92"You are given a string $$$s$$$ consisting only of first $$$20$$$ lowercase Latin letters ('a', 'b', ..., 't').Recall that the substring $$$s[l; r]$$$ of the string $$$s$$$ is the string $$$s_l s_{l + 1} \dots s_r$$$. For example, the substrings of ""codeforces"" are ""code"", ""force"", ""f"", ""for"", but not ""coder"" and ""top"".You can perform the following operation no more than once: choose some substring $$$s[l; r]$$$ and reverse it (i.e. the string $$$s_l s_{l + 1} \dots s_r$$$ becomes $$$s_r s_{r - 1} \dots s_l$$$).Your goal is to maximize the length of the maximum substring of $$$s$$$ consisting of distinct (i.e. unique) characters.The string consists of distinct characters if no character in this string appears more than once. For example, strings ""abcde"", ""arctg"" and ""minecraft"" consist of distinct characters but strings ""codeforces"", ""abacaba"" do not consist of distinct characters.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"93"Gildong recently learned how to find the longest increasing subsequence (LIS) in $$$O(n\log{n})$$$ time for a sequence of length $$$n$$$. He wants to test himself if he can implement it correctly, but he couldn't find any online judges that would do it (even though there are actually many of them). So instead he's going to make a quiz for you about making permutations of $$$n$$$ distinct integers between $$$1$$$ and $$$n$$$, inclusive, to test his code with your output.The quiz is as follows.Gildong provides a string of length $$$n-1$$$, consisting of characters '<' and '>' only. The $$$i$$$-th (1-indexed) character is the comparison result between the $$$i$$$-th element and the $$$i+1$$$-st element of the sequence. If the $$$i$$$-th character of the string is '<', then the $$$i$$$-th element of the sequence is less than the $$$i+1$$$-st element. If the $$$i$$$-th character of the string is '>', then the $$$i$$$-th element of the sequence is greater than the $$$i+1$$$-st element.He wants you to find two possible sequences (not necessarily distinct) consisting of $$$n$$$ distinct integers between $$$1$$$ and $$$n$$$, inclusive, each satisfying the comparison results, where the length of the LIS of the first sequence is minimum possible, and the length of the LIS of the second sequence is maximum possible.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"94"$$$n$$$ players are playing a game. There are two different maps in the game. For each player, we know his strength on each map. When two players fight on a specific map, the player with higher strength on that map always wins. No two players have the same strength on the same map. You are the game master and want to organize a tournament. There will be a total of $$$n-1$$$ battles. While there is more than one player in the tournament, choose any map and any two remaining players to fight on it. The player who loses will be eliminated from the tournament. In the end, exactly one player will remain, and he is declared the winner of the tournament. For each player determine if he can win the tournament.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"95"Yash has recently learnt about the Fibonacci sequence and is very excited about it. He calls a sequence Fibonacci-ish if   the sequence consists of at least two elements  f0 and f1 are arbitrary  fn + 2 = fn + 1 + fn for all n ≥ 0. You are given some sequence of integers a1, a2, ..., an. Your task is rearrange elements of this sequence in such a way that its longest possible prefix is Fibonacci-ish sequence.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"96"You are given a functional graph. It is a directed graph, in which from each vertex goes exactly one arc. The vertices are numerated from 0 to n - 1.Graph is given as the array f0, f1, ..., fn - 1, where fi — the number of vertex to which goes the only arc from the vertex i. Besides you are given array with weights of the arcs w0, w1, ..., wn - 1, where wi — the arc weight from i to fi.    The graph from the first sample test. Also you are given the integer k (the length of the path) and you need to find for each vertex two numbers si and mi, where:  si — the sum of the weights of all arcs of the path with length equals to k which starts from the vertex i;  mi — the minimal weight from all arcs on the path with length k which starts from the vertex i. The length of the path is the number of arcs on this path.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"97"You are given an integer $$$n$$$. In one move, you can either multiply $$$n$$$ by two or divide $$$n$$$ by $$$6$$$ (if it is divisible by $$$6$$$ without the remainder).Your task is to find the minimum number of moves needed to obtain $$$1$$$ from $$$n$$$ or determine if it's impossible to do that.You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"98"You are given an array $$$a$$$ of $$$n$$$ positive integers. Let $$$\text{LIS}(a)$$$ denote the length of longest strictly increasing subsequence of $$$a$$$. For example,  $$$\text{LIS}([2, \underline{1}, 1, \underline{3}])$$$ = $$$2$$$.  $$$\text{LIS}([\underline{3}, \underline{5}, \underline{10}, \underline{20}])$$$ = $$$4$$$.  $$$\text{LIS}([3, \underline{1}, \underline{2}, \underline{4}])$$$ = $$$3$$$.  We define array $$$a'$$$ as the array obtained after reversing the array $$$a$$$ i.e. $$$a' = [a_n, a_{n-1}, \ldots , a_1]$$$.The beauty of array $$$a$$$ is defined as $$$min(\text{LIS}(a),\text{LIS}(a'))$$$.Your task is to determine the maximum possible beauty of the array $$$a$$$ if you can rearrange the array $$$a$$$ arbitrarily.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"99"There is a robot in a warehouse and $$$n$$$ packages he wants to collect. The warehouse can be represented as a coordinate grid. Initially, the robot stays at the point $$$(0, 0)$$$. The $$$i$$$-th package is at the point $$$(x_i, y_i)$$$. It is guaranteed that there are no two packages at the same point. It is also guaranteed that the point $$$(0, 0)$$$ doesn't contain a package.The robot is semi-broken and only can move up ('U') and right ('R'). In other words, in one move the robot can go from the point $$$(x, y)$$$ to the point ($$$x + 1, y$$$) or to the point $$$(x, y + 1)$$$.As we say above, the robot wants to collect all $$$n$$$ packages (in arbitrary order). He wants to do it with the minimum possible number of moves. If there are several possible traversals, the robot wants to choose the lexicographically smallest path.The string $$$s$$$ of length $$$n$$$ is lexicographically less than the string $$$t$$$ of length $$$n$$$ if there is some index $$$1 \le j \le n$$$ that for all $$$i$$$ from $$$1$$$ to $$$j-1$$$ $$$s_i = t_i$$$ and $$$s_j < t_j$$$. It is the standard comparison of string, like in a dictionary. Most programming languages compare strings in this way.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"100"Polycarp was recently given a set of $$$n$$$ (number $$$n$$$ — even) dominoes. Each domino contains two integers from $$$1$$$ to $$$n$$$.Can he divide all the dominoes into two sets so that all the numbers on the dominoes of each set are different? Each domino must go into exactly one of the two sets.For example, if he has $$$4$$$ dominoes: $$$\{1, 4\}$$$, $$$\{1, 3\}$$$, $$$\{3, 2\}$$$ and $$$\{4, 2\}$$$, then Polycarp will be able to divide them into two sets in the required way. The first set can include the first and third dominoes ($$$\{1, 4\}$$$ and $$$\{3, 2\}$$$), and the second set — the second and fourth ones ($$$\{1, 3\}$$$ and $$$\{4, 2\}$$$).",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"101"Everybody knows what an arithmetic progression is. Let us remind you just in case that an arithmetic progression is such sequence of numbers a1, a2, ..., an of length n, that the following condition fulfills: a2 - a1 = a3 - a2 = a4 - a3 = ... = ai + 1 - ai = ... = an - an - 1.For example, sequences [1, 5], [10], [5, 4, 3] are arithmetic progressions and sequences [1, 3, 2], [1, 2, 4] are not.Alexander has n cards containing integers. Arthur wants to give Alexander exactly one more card with a number so that he could use the resulting n + 1 cards to make an arithmetic progression (Alexander has to use all of his cards).Arthur has already bought a card but he hasn't written a number on it. Help him, print all integers that you can write on a card so that the described condition fulfilled.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"102"DZY has a sequence a, consisting of n integers.We'll call a sequence ai, ai + 1, ..., aj (1 ≤ i ≤ j ≤ n) a subsegment of the sequence a. The value (j - i + 1) denotes the length of the subsegment.Your task is to find the longest subsegment of a, such that it is possible to change at most one number (change one number to any integer you want) from the subsegment to make the subsegment strictly increasing.You only need to output the length of the subsegment you find.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"103"During cleaning the coast, Alice found $$$n$$$ piles of stones. The $$$i$$$-th pile has $$$a_i$$$ stones.Piles $$$i$$$ and $$$i + 1$$$ are neighbouring for all $$$1 \leq i \leq n - 1$$$. If pile $$$i$$$ becomes empty, piles $$$i - 1$$$ and $$$i + 1$$$ doesn't become neighbouring.Alice is too lazy to remove these stones, so she asked you to take this duty. She allowed you to do only the following operation:   Select two neighboring piles and, if both of them are not empty, remove one stone from each of them. Alice understands that sometimes it's impossible to remove all stones with the given operation, so she allowed you to use the following superability:   Before the start of cleaning, you can select two neighboring piles and swap them. Determine, if it is possible to remove all stones using the superability not more than once.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"104"Monocarp is planning to host a martial arts tournament. There will be three divisions based on weight: lightweight, middleweight and heavyweight. The winner of each division will be determined by a single elimination system.In particular, that implies that the number of participants in each division should be a power of two. Additionally, each division should have a non-zero amount of participants.$$$n$$$ participants have registered for the tournament so far, the $$$i$$$-th of them weighs $$$a_i$$$. To split participants into divisions, Monocarp is going to establish two integer weight boundaries $$$x$$$ and $$$y$$$ ($$$x < y$$$). All participants who weigh strictly less than $$$x$$$ will be considered lightweight. All participants who weigh greater or equal to $$$y$$$ will be considered heavyweight. The remaining participants will be considered middleweight.It's possible that the distribution doesn't make the number of participants in each division a power of two. It can also lead to empty divisions. To fix the issues, Monocarp can invite an arbitrary number of participants to each division.Note that Monocarp can't kick out any of the $$$n$$$ participants who have already registered for the tournament.However, he wants to invite as little extra participants as possible. Help Monocarp to choose $$$x$$$ and $$$y$$$ in such a way that the total amount of extra participants required is as small as possible. Output that amount.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"105"Inzane finally found Zane with a lot of money to spare, so they together decided to establish a country of their own.Ruling a country is not an easy job. Thieves and terrorists are always ready to ruin the country's peace. To fight back, Zane and Inzane have enacted a very effective law: from each city it must be possible to reach a police station by traveling at most d kilometers along the roads.  There are n cities in the country, numbered from 1 to n, connected only by exactly n - 1 roads. All roads are 1 kilometer long. It is initially possible to travel from a city to any other city using these roads. The country also has k police stations located in some cities. In particular, the city's structure satisfies the requirement enforced by the previously mentioned law. Also note that there can be multiple police stations in one city.However, Zane feels like having as many as n - 1 roads is unnecessary. The country is having financial issues, so it wants to minimize the road maintenance cost by shutting down as many roads as possible.Help Zane find the maximum number of roads that can be shut down without breaking the law. Also, help him determine such roads.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"106"Valera has 2·n cubes, each cube contains an integer from 10 to 99. He arbitrarily chooses n cubes and puts them in the first heap. The remaining cubes form the second heap. Valera decided to play with cubes. During the game he takes a cube from the first heap and writes down the number it has. Then he takes a cube from the second heap and write out its two digits near two digits he had written (to the right of them). In the end he obtained a single fourdigit integer — the first two digits of it is written on the cube from the first heap, and the second two digits of it is written on the second cube from the second heap.Valera knows arithmetic very well. So, he can easily count the number of distinct fourdigit numbers he can get in the game. The other question is: how to split cubes into two heaps so that this number (the number of distinct fourdigit integers Valera can get) will be as large as possible?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"107"Little girl Tanya climbs the stairs inside a multi-storey building. Every time Tanya climbs a stairway, she starts counting steps from $$$1$$$ to the number of steps in this stairway. She speaks every number aloud. For example, if she climbs two stairways, the first of which contains $$$3$$$ steps, and the second contains $$$4$$$ steps, she will pronounce the numbers $$$1, 2, 3, 1, 2, 3, 4$$$.You are given all the numbers pronounced by Tanya. How many stairways did she climb? Also, output the number of steps in each stairway.The given sequence will be a valid sequence that Tanya could have pronounced when climbing one or more stairways.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"108"Your classmate, whom you do not like because he is boring, but whom you respect for his intellect, has two strings: $$$s$$$ of length $$$n$$$ and $$$t$$$ of length $$$m$$$.A sequence $$$p_1, p_2, \ldots, p_m$$$, where $$$1 \leq p_1 < p_2 < \ldots < p_m \leq n$$$, is called beautiful, if $$$s_{p_i} = t_i$$$ for all $$$i$$$ from $$$1$$$ to $$$m$$$. The width of a sequence is defined as $$$\max\limits_{1 \le i < m} \left(p_{i + 1} - p_i\right)$$$.Please help your classmate to identify the beautiful sequence with the maximum width. Your classmate promised you that for the given strings $$$s$$$ and $$$t$$$ there is at least one beautiful sequence.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"109"Прошло много лет, и на вечеринке снова встретились n друзей. С момента последней встречи техника шагнула далеко вперёд, появились фотоаппараты с автоспуском, и теперь не требуется, чтобы один из друзей стоял с фотоаппаратом, и, тем самым, оказывался не запечатлённым на снимке.Упрощенно процесс фотографирования можно описать следующим образом. На фотографии каждый из друзей занимает прямоугольник из пикселей: в стоячем положении i-й из них занимает прямоугольник ширины wi пикселей и высоты hi пикселей. Но также, при фотографировании каждый человек может лечь, и тогда он будет занимать прямоугольник ширины hi пикселей и высоты wi пикселей.Общая фотография будет иметь размеры W × H, где W — суммарная ширина всех прямоугольников-людей, а H — максимальная из высот. Друзья хотят определить, какую минимальную площадь может иметь общая фотография. Помогите им в этом.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"110"There are $$$n$$$ armchairs, numbered from $$$1$$$ to $$$n$$$ from left to right. Some armchairs are occupied by people (at most one person per armchair), others are not. The number of occupied armchairs is not greater than $$$\frac{n}{2}$$$.For some reason, you would like to tell people to move from their armchairs to some other ones. If the $$$i$$$-th armchair is occupied by someone and the $$$j$$$-th armchair is not, you can tell the person sitting in the $$$i$$$-th armchair to move to the $$$j$$$-th armchair. The time it takes a person to move from the $$$i$$$-th armchair to the $$$j$$$-th one is $$$|i - j|$$$ minutes. You may perform this operation any number of times, but these operations must be done sequentially, i. e. you cannot tell a person to move until the person you asked to move in the last operation has finished moving to their destination armchair.You want to achieve the following situation: every seat that was initially occupied must be free. What is the minimum time you need to do it?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"111"Olya has got a directed non-weighted graph, consisting of n vertexes and m edges. We will consider that the graph vertexes are indexed from 1 to n in some manner. Then for any graph edge that goes from vertex v to vertex u the following inequation holds: v < u.Now Olya wonders, how many ways there are to add an arbitrary (possibly zero) number of edges to the graph so as the following conditions were met:  You can reach vertexes number i + 1, i + 2, ..., n from any vertex number i (i < n).  For any graph edge going from vertex v to vertex u the following inequation fulfills: v < u.  There is at most one edge between any two vertexes.  The shortest distance between the pair of vertexes i, j (i < j), for which j - i ≤ k holds, equals j - i edges.  The shortest distance between the pair of vertexes i, j (i < j), for which j - i > k holds, equals either j - i or j - i - k edges.  We will consider two ways distinct, if there is the pair of vertexes i, j (i < j), such that first resulting graph has an edge from i to j and the second one doesn't have it.Help Olya. As the required number of ways can be rather large, print it modulo 1000000007 (109 + 7).",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"112"This is an interactive problem.ICPC Assiut Community decided to hold a unique chess contest, and you were chosen to control a queen and hunt down the hidden king, while a member of ICPC Assiut Community controls this king.You compete on an $$$8\times8$$$ chessboard, the rows are numerated from top to bottom, and the columns are numerated left to right, and the cell in row $$$x$$$ and column $$$y$$$ is denoted as $$$(x, y)$$$.In one turn you can move the queen to any of the squares on the same horizontal line, vertical line, or any of the diagonals. For example, if the queen was on square ($$$4$$$, $$$5$$$), you can move to ($$$q_1$$$, $$$5$$$), ($$$4$$$, $$$q_1$$$), ($$$q_1$$$, $$$9-q_1$$$), or ($$$q_2$$$, $$$q_2+1$$$) where ($$$1 \le q_1 \le 8$$$, $$$q_1 \ne 4$$$, $$$1 \le q_2 \le 7$$$, $$$q_2 \ne 4$$$). Note that the queen cannot stay on its current cell.   In one turn, the king can move ""Right"", ""Left"", ""Up"", ""Down"", ""Down-Right"", ""Down-Left"", ""Up-Left"", or ""Up-Right"" such that he doesn't get out of the board. The king cannot move into a cell that is on the same row, column or diagonal with the queen (including the position of the queen itself). For example, if the king was on square ($$$4$$$, $$$5$$$), he can move to ($$$4+k_1$$$, $$$5+k_2$$$) where ($$$-1 \le k_1,k_2 \le 1$$$, $$$(k_1, k_2) \ne (0, 0)$$$).   At the start of the game, you should place the queen at any location on the board, and this is done once per game. After that the king is secretly placed at any cell different from the queen's location. You do not know the position of the king. Then, the king and the queen take turns with the king moving first. The king moves to one of the possible directions (""Right"", ""Down"", ""Up-Left"", etc.), and you are only given the direction it moves to. After that, you should move your queen by declaring the square to which your queen will move. The game follows like this until you win the game or run out of moves.You win if the king has no valid moves. You lose if after $$$130$$$ moves of the queen the king still has valid moves.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"113"Professor GukiZ has two arrays of integers, a and b. Professor wants to make the sum of the elements in the array a sa as close as possible to the sum of the elements in the array b sb. So he wants to minimize the value v = |sa - sb|.In one operation professor can swap some element from the array a and some element from the array b. For example if the array a is [5, 1, 3, 2, 4] and the array b is [3, 3, 2] professor can swap the element 5 from the array a and the element 2 from the array b and get the new array a [2, 1, 3, 2, 4] and the new array b [3, 3, 5].Professor doesn't want to make more than two swaps. Find the minimal value v and some sequence of no more than two swaps that will lead to the such value v. Professor makes swaps one by one, each new swap he makes with the new arrays a and b.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"114"Monocarp has drawn a tree (an undirected connected acyclic graph) and then has given each vertex an index. All indices are distinct numbers from $$$1$$$ to $$$n$$$. For every edge $$$e$$$ of this tree, Monocarp has written two numbers: the maximum indices of the vertices of the two components formed if the edge $$$e$$$ (and only this edge) is erased from the tree.Monocarp has given you a list of $$$n - 1$$$ pairs of numbers. He wants you to provide an example of a tree that will produce the said list if this tree exists. If such tree does not exist, say so.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"115"Petya loves football very much, especially when his parents aren't home. Each morning he comes to the yard, gathers his friends and they play all day. From time to time they have a break to have some food or do some chores (for example, water the flowers).The key in football is to divide into teams fairly before the game begins. There are n boys playing football in the yard (including Petya), each boy's football playing skill is expressed with a non-negative characteristic ai (the larger it is, the better the boy plays). Let's denote the number of players in the first team as x, the number of players in the second team as y, the individual numbers of boys who play for the first team as pi and the individual numbers of boys who play for the second team as qi. Division n boys into two teams is considered fair if three conditions are fulfilled:  Each boy plays for exactly one team (x + y = n).  The sizes of teams differ in no more than one (|x - y| ≤ 1).  The total football playing skills for two teams differ in no more than by the value of skill the best player in the yard has. More formally: Your task is to help guys divide into two teams fairly. It is guaranteed that a fair division into two teams always exists.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"116"You are given a directed acyclic graph with $$$n$$$ vertices and $$$m$$$ edges. For all edges $$$a \to b$$$ in the graph, $$$a < b$$$ holds.You need to find the number of pairs of vertices $$$x$$$, $$$y$$$, such that $$$x > y$$$ and after adding the edge $$$x \to y$$$ to the graph, it has a Hamiltonian path. ",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"117"It's the year 4527 and the tanks game that we all know and love still exists. There also exists Great Gena's code, written in 2016. The problem this code solves is: given the number of tanks that go into the battle from each country, find their product. If it is turns to be too large, then the servers might have not enough time to assign tanks into teams and the whole game will collapse!There are exactly n distinct countries in the world and the i-th country added ai tanks to the game. As the developers of the game are perfectionists, the number of tanks from each country is beautiful. A beautiful number, according to the developers, is such number that its decimal representation consists only of digits '1' and '0', moreover it contains at most one digit '1'. However, due to complaints from players, some number of tanks of one country was removed from the game, hence the number of tanks of this country may not remain beautiful.Your task is to write the program that solves exactly the same problem in order to verify Gena's code correctness. Just in case.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"118"Ever since Kalevitch, a famous Berland abstractionist, heard of fractals, he made them the main topic of his canvases. Every morning the artist takes a piece of graph paper and starts with making a model of his future canvas. He takes a square as big as n × n squares and paints some of them black. Then he takes a clean square piece of paper and paints the fractal using the following algorithm: Step 1. The paper is divided into n2 identical squares and some of them are painted black according to the model.Step 2. Every square that remains white is divided into n2 smaller squares and some of them are painted black according to the model.Every following step repeats step 2.  Unfortunately, this tiresome work demands too much time from the painting genius. Kalevitch has been dreaming of making the process automatic to move to making 3D or even 4D fractals.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"119"Vova is again playing some computer game, now an RPG. In the game Vova's character received a quest: to slay the fearsome monster called Modcrab.After two hours of playing the game Vova has tracked the monster and analyzed its tactics. The Modcrab has h2 health points and an attack power of a2. Knowing that, Vova has decided to buy a lot of strong healing potions and to prepare for battle.Vova's character has h1 health points and an attack power of a1. Also he has a large supply of healing potions, each of which increases his current amount of health points by c1 when Vova drinks a potion. All potions are identical to each other. It is guaranteed that c1 > a2.The battle consists of multiple phases. In the beginning of each phase, Vova can either attack the monster (thus reducing its health by a1) or drink a healing potion (it increases Vova's health by c1; Vova's health can exceed h1). Then, if the battle is not over yet, the Modcrab attacks Vova, reducing his health by a2. The battle ends when Vova's (or Modcrab's) health drops to 0 or lower. It is possible that the battle ends in a middle of a phase after Vova's attack.Of course, Vova wants to win the fight. But also he wants to do it as fast as possible. So he wants to make up a strategy that will allow him to win the fight after the minimum possible number of phases.Help Vova to make up a strategy! You may assume that Vova never runs out of healing potions, and that he can always win.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"120"Mike and Ann are sitting in the classroom. The lesson is boring, so they decided to play an interesting game. Fortunately, all they need to play this game is a string $$$s$$$ and a number $$$k$$$ ($$$0 \le k < |s|$$$).At the beginning of the game, players are given a substring of $$$s$$$ with left border $$$l$$$ and right border $$$r$$$, both equal to $$$k$$$ (i.e. initially $$$l=r=k$$$). Then players start to make moves one by one, according to the following rules: A player chooses $$$l^{\prime}$$$ and $$$r^{\prime}$$$ so that $$$l^{\prime} \le l$$$, $$$r^{\prime} \ge r$$$ and $$$s[l^{\prime}, r^{\prime}]$$$ is lexicographically less than $$$s[l, r]$$$. Then the player changes $$$l$$$ and $$$r$$$ in this way: $$$l := l^{\prime}$$$, $$$r := r^{\prime}$$$. Ann moves first. The player, that can't make a move loses.Recall that a substring $$$s[l, r]$$$ ($$$l \le r$$$) of a string $$$s$$$ is a continuous segment of letters from s that starts at position $$$l$$$ and ends at position $$$r$$$. For example, ""ehn"" is a substring ($$$s[3, 5]$$$) of ""aaaehnsvz"" and ""ahz"" is not.Mike and Ann were playing so enthusiastically that they did not notice the teacher approached them. Surprisingly, the teacher didn't scold them, instead of that he said, that he can figure out the winner of the game before it starts, even if he knows only $$$s$$$ and $$$k$$$.Unfortunately, Mike and Ann are not so keen in the game theory, so they ask you to write a program, that takes $$$s$$$ and determines the winner for all possible $$$k$$$.","['games', 'strings']","[1, 0, 0, 0, 0, 0, 1, 0]"121"$$$ \def\myred#1{\color{red}{\underline{\bf{#1}}}} \def\myblue#1{\color{blue}{\overline{\bf{#1}}}} $$$ $$$\def\RED{\myred{Red}} \def\BLUE{\myblue{Blue}}$$$You are given a sequence of $$$n$$$ non-negative integers $$$a_1, a_2, \ldots, a_n$$$. Initially, all the elements of the sequence are unpainted. You can paint each number $$$\RED$$$ or $$$\BLUE$$$ (but not both), or leave it unpainted. For a color $$$c$$$, $$$\text{Count}(c)$$$ is the number of elements in the sequence painted with that color and $$$\text{Sum}(c)$$$ is the sum of the elements in the sequence painted with that color.For example, if the given sequence is $$$[2, 8, 6, 3, 1]$$$ and it is painted this way: $$$[\myblue{2}, 8, \myred{6}, \myblue{3}, 1]$$$ (where $$$6$$$ is painted red, $$$2$$$ and $$$3$$$ are painted blue, $$$1$$$ and $$$8$$$ are unpainted) then $$$\text{Sum}(\RED)=6$$$, $$$\text{Sum}(\BLUE)=2+3=5$$$, $$$\text{Count}(\RED)=1$$$, and $$$\text{Count}(\BLUE)=2$$$.Determine if it is possible to paint the sequence so that $$$\text{Sum}(\RED) > \text{Sum}(\BLUE)$$$ and $$$\text{Count}(\RED) < \text{Count}(\BLUE)$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"122"Heidi is a statistician to the core, and she likes to study the evolution of marmot populations in each of V (1 ≤ V ≤ 100) villages! So it comes that every spring, when Heidi sees the first snowdrops sprout in the meadows around her barn, she impatiently dons her snowshoes and sets out to the Alps, to welcome her friends the marmots to a new season of thrilling adventures.Arriving in a village, Heidi asks each and every marmot she comes across for the number of inhabitants of that village. This year, the marmots decide to play an April Fools' joke on Heidi. Instead of consistently providing the exact number of inhabitants P (10 ≤ P ≤ 1000) of the village, they respond with a random non-negative integer k, drawn from one of two types of probability distributions:  Poisson (d'avril) distribution: the probability of getting an answer k is  for k = 0, 1, 2, 3, ...,  Uniform distribution: the probability of getting an answer k is  for k = 0, 1, 2, ..., 2P. Heidi collects exactly 250 answers per village. Every village follows either the Poisson or the uniform distribution. Heidi cannot tell marmots apart, so she may query some marmots several times, and each time the marmot will answer with a new number drawn from the village's distribution.Can you help Heidi to find out whether a village follows a Poisson or a uniform distribution?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"123"You are given an array $$$a$$$ consisting of $$$n$$$ integers.Let $$$min(l, r)$$$ be the minimum value among $$$a_l, a_{l + 1}, \ldots, a_r$$$ and $$$max(l, r)$$$ be the maximum value among $$$a_l, a_{l + 1}, \ldots, a_r$$$.Your task is to choose three positive (greater than $$$0$$$) integers $$$x$$$, $$$y$$$ and $$$z$$$ such that:  $$$x + y + z = n$$$;  $$$max(1, x) = min(x + 1, x + y) = max(x + y + 1, n)$$$. In other words, you have to split the array $$$a$$$ into three consecutive non-empty parts that cover the whole array and the maximum in the first part equals the minimum in the second part and equals the maximum in the third part (or determine it is impossible to find such a partition).Among all such triples (partitions), you can choose any.You have to answer $$$t$$$ independent test cases.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"124"Nikephoros and Polycarpus play rock-paper-scissors. The loser gets pinched (not too severely!).Let us remind you the rules of this game. Rock-paper-scissors is played by two players. In each round the players choose one of three items independently from each other. They show the items with their hands: a rock, scissors or paper. The winner is determined by the following rules: the rock beats the scissors, the scissors beat the paper and the paper beats the rock. If the players choose the same item, the round finishes with a draw.Nikephoros and Polycarpus have played n rounds. In each round the winner gave the loser a friendly pinch and the loser ended up with a fresh and new red spot on his body. If the round finished in a draw, the players did nothing and just played on.Nikephoros turned out to have worked out the following strategy: before the game began, he chose some sequence of items A = (a1, a2, ..., am), and then he cyclically showed the items from this sequence, starting from the first one. Cyclically means that Nikephoros shows signs in the following order: a1, a2, ..., am, a1, a2, ..., am, a1, ... and so on. Polycarpus had a similar strategy, only he had his own sequence of items B = (b1, b2, ..., bk).Determine the number of red spots on both players after they've played n rounds of the game. You can consider that when the game began, the boys had no red spots on them.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"125"A string is called bracket sequence if it does not contain any characters other than ""("" and "")"". A bracket sequence is called regular (shortly, RBS) if it is possible to obtain correct arithmetic expression by inserting characters ""+"" and ""1"" into this sequence. For example, """", ""(())"" and ""()()"" are RBS and "")("" and ""(()"" are not.We can see that each opening bracket in RBS is paired with some closing bracket, and, using this fact, we can define nesting depth of the RBS as maximum number of bracket pairs, such that the $$$2$$$-nd pair lies inside the $$$1$$$-st one, the $$$3$$$-rd one — inside the $$$2$$$-nd one and so on. For example, nesting depth of """" is $$$0$$$, ""()()()"" is $$$1$$$ and ""()((())())"" is $$$3$$$.Now, you are given RBS $$$s$$$ of even length $$$n$$$. You should color each bracket of $$$s$$$ into one of two colors: red or blue. Bracket sequence $$$r$$$, consisting only of red brackets, should be RBS, and bracket sequence, consisting only of blue brackets $$$b$$$, should be RBS. Any of them can be empty. You are not allowed to reorder characters in $$$s$$$, $$$r$$$ or $$$b$$$. No brackets can be left uncolored.Among all possible variants you should choose one that minimizes maximum of $$$r$$$'s and $$$b$$$'s nesting depth. If there are multiple solutions you can print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"126"A boy Petya loves chess very much. He even came up with a chess piece of his own, a semiknight. The semiknight can move in any of these four directions: 2 squares forward and 2 squares to the right, 2 squares forward and 2 squares to the left, 2 squares backward and 2 to the right and 2 squares backward and 2 to the left. Naturally, the semiknight cannot move beyond the limits of the chessboard.Petya put two semiknights on a standard chessboard. Petya simultaneously moves with both semiknights. The squares are rather large, so after some move the semiknights can meet, that is, they can end up in the same square. After the meeting the semiknights can move on, so it is possible that they meet again. Petya wonders if there is such sequence of moves when the semiknights meet. Petya considers some squares bad. That is, they do not suit for the meeting. The semiknights can move through these squares but their meetings in these squares don't count.Petya prepared multiple chess boards. Help Petya find out whether the semiknights can meet on some good square for each board.Please see the test case analysis.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"127"You are given an array a. Some element of this array ai is a local minimum iff it is strictly less than both of its neighbours (that is, ai < ai - 1 and ai < ai + 1). Also the element can be called local maximum iff it is strictly greater than its neighbours (that is, ai > ai - 1 and ai > ai + 1). Since a1 and an have only one neighbour each, they are neither local minima nor local maxima.An element is called a local extremum iff it is either local maximum or local minimum. Your task is to calculate the number of local extrema in the given array.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"128"Let $$$s$$$ be some string consisting of symbols ""0"" or ""1"". Let's call a string $$$t$$$ a substring of string $$$s$$$, if there exists such number $$$1 \leq l \leq |s| - |t| + 1$$$ that $$$t = s_l s_{l+1} \ldots s_{l + |t| - 1}$$$. Let's call a substring $$$t$$$ of string $$$s$$$ unique, if there exist only one such $$$l$$$. For example, let $$$s = $$$""1010111"". A string $$$t = $$$""010"" is an unique substring of $$$s$$$, because $$$l = 2$$$ is the only one suitable number. But, for example $$$t = $$$""10"" isn't a unique substring of $$$s$$$, because $$$l = 1$$$ and $$$l = 3$$$ are suitable. And for example $$$t =$$$""00"" at all isn't a substring of $$$s$$$, because there is no suitable $$$l$$$.Today Vasya solved the following problem at the informatics lesson: given a string consisting of symbols ""0"" and ""1"", the task is to find the length of its minimal unique substring. He has written a solution to this problem and wants to test it. He is asking you to help him.You are given $$$2$$$ positive integers $$$n$$$ and $$$k$$$, such that $$$(n \bmod 2) = (k \bmod 2)$$$, where $$$(x \bmod 2)$$$ is operation of taking remainder of $$$x$$$ by dividing on $$$2$$$. Find any string $$$s$$$ consisting of $$$n$$$ symbols ""0"" or ""1"", such that the length of its minimal unique substring is equal to $$$k$$$.","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"129There are $$$n$$$ cities and $$$m$$$ roads in Berland. Each road connects a pair of cities. The roads in Berland are one-way.What is the minimum number of new roads that need to be built to make all the cities reachable from the capital?New roads will also be one-way.,['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"130"Recall that a permutation of length $$$n$$$ is an array where each element from $$$1$$$ to $$$n$$$ occurs exactly once.For a fixed positive integer $$$d$$$, let's define the cost of the permutation $$$p$$$ of length $$$n$$$ as the number of indices $$$i$$$ $$$(1 \le i < n)$$$ such that $$$p_i \cdot d = p_{i + 1}$$$.For example, if $$$d = 3$$$ and $$$p = [5, 2, 6, 7, 1, 3, 4]$$$, then the cost of such a permutation is $$$2$$$, because $$$p_2 \cdot 3 = p_3$$$ and $$$p_5 \cdot 3 = p_6$$$.Your task is the following one: for a given value $$$n$$$, find the permutation of length $$$n$$$ and the value $$$d$$$ with maximum possible cost (over all ways to choose the permutation and $$$d$$$). If there are multiple answers, then print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"131"Recently, Petya learned about a new game ""Slay the Dragon"". As the name suggests, the player will have to fight with dragons. To defeat a dragon, you have to kill it and defend your castle. To do this, the player has a squad of $$$n$$$ heroes, the strength of the $$$i$$$-th hero is equal to $$$a_i$$$.According to the rules of the game, exactly one hero should go kill the dragon, all the others will defend the castle. If the dragon's defense is equal to $$$x$$$, then you have to send a hero with a strength of at least $$$x$$$ to kill it. If the dragon's attack power is $$$y$$$, then the total strength of the heroes defending the castle should be at least $$$y$$$.The player can increase the strength of any hero by $$$1$$$ for one gold coin. This operation can be done any number of times.There are $$$m$$$ dragons in the game, the $$$i$$$-th of them has defense equal to $$$x_i$$$ and attack power equal to $$$y_i$$$. Petya was wondering what is the minimum number of coins he needs to spend to defeat the $$$i$$$-th dragon.Note that the task is solved independently for each dragon (improvements are not saved).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"132"Vova has taken his summer practice this year and now he should write a report on how it went.Vova has already drawn all the tables and wrote down all the formulas. Moreover, he has already decided that the report will consist of exactly $$$n$$$ pages and the $$$i$$$-th page will include $$$x_i$$$ tables and $$$y_i$$$ formulas. The pages are numbered from $$$1$$$ to $$$n$$$.Vova fills the pages one after another, he can't go filling page $$$i + 1$$$ before finishing page $$$i$$$ and he can't skip pages. However, if he draws strictly more than $$$k$$$ tables in a row or writes strictly more than $$$k$$$ formulas in a row then he will get bored. Vova wants to rearrange tables and formulas in each page in such a way that he doesn't get bored in the process. Vova can't move some table or some formula to another page.Note that the count doesn't reset on the start of the new page. For example, if the page ends with $$$3$$$ tables and the next page starts with $$$5$$$ tables, then it's counted as $$$8$$$ tables in a row.Help Vova to determine if he can rearrange tables and formulas on each page in such a way that there is no more than $$$k$$$ tables in a row and no more than $$$k$$$ formulas in a row.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"133"You are given the array $$$a$$$ consisting of $$$n$$$ elements and the integer $$$k \le n$$$.You want to obtain at least $$$k$$$ equal elements in the array $$$a$$$. In one move, you can make one of the following two operations:  Take one of the minimum elements of the array and increase its value by one (more formally, if the minimum value of $$$a$$$ is $$$mn$$$ then you choose such index $$$i$$$ that $$$a_i = mn$$$ and set $$$a_i := a_i + 1$$$);  take one of the maximum elements of the array and decrease its value by one (more formally, if the maximum value of $$$a$$$ is $$$mx$$$ then you choose such index $$$i$$$ that $$$a_i = mx$$$ and set $$$a_i := a_i - 1$$$). Your task is to calculate the minimum number of moves required to obtain at least $$$k$$$ equal elements in the array.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"134"Основой любой социальной сети является отношение дружбы между двумя пользователями в том или ином смысле. В одной известной социальной сети дружба симметрична, то есть если a является другом b, то b также является другом a. В этой же сети есть функция, которая демонстрирует множество людей, имеющих высокую вероятность быть знакомыми для пользователя. Эта функция работает следующим образом. Зафиксируем пользователя x. Пусть некоторый другой человек y, не являющийся другом x на текущий момент, является другом не менее, чем для k% друзей x. Тогда он является предполагаемым другом для x.У каждого человека в социальной сети есть свой уникальный идентификатор — это целое число от 1 до 109. Вам дан список пар пользователей, являющихся друзьями. Определите для каждого упомянутого пользователя множество его предполагаемых друзей.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"135"After bracket sequences Arthur took up number theory. He has got a new favorite sequence of length n (a1, a2, ..., an), consisting of integers and integer k, not exceeding n.This sequence had the following property: if you write out the sums of all its segments consisting of k consecutive elements (a1  +  a2 ...  +  ak,  a2  +  a3  +  ...  +  ak + 1,  ...,  an - k + 1  +  an - k + 2  +  ...  +  an), then those numbers will form strictly increasing sequence.For example, for the following sample: n = 5,  k = 3,  a = (1,  2,  4,  5,  6) the sequence of numbers will look as follows: (1  +  2  +  4,  2  +  4  +  5,  4  +  5  +  6) = (7,  11,  15), that means that sequence a meets the described property. Obviously the sequence of sums will have n - k + 1 elements.Somebody (we won't say who) replaced some numbers in Arthur's sequence by question marks (if this number is replaced, it is replaced by exactly one question mark). We need to restore the sequence so that it meets the required property and also minimize the sum |ai|, where |ai| is the absolute value of ai.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"136"After years of hard work scientists invented an absolutely new e-reader display. The new display has a larger resolution, consumes less energy and its production is cheaper. And besides, one can bend it. The only inconvenience is highly unusual management. For that very reason the developers decided to leave the e-readers' software to programmers.The display is represented by n × n square of pixels, each of which can be either black or white. The display rows are numbered with integers from 1 to n upside down, the columns are numbered with integers from 1 to n from the left to the right. The display can perform commands like ""x, y"". When a traditional display fulfills such command, it simply inverts a color of (x, y), where x is the row number and y is the column number. But in our new display every pixel that belongs to at least one of the segments (x, x) - (x, y) and (y, y) - (x, y) (both ends of both segments are included) inverts a color.For example, if initially a display 5 × 5 in size is absolutely white, then the sequence of commands (1, 4), (3, 5), (5, 1), (3, 3) leads to the following changes:  You are an e-reader software programmer and you should calculate minimal number of commands needed to display the picture. You can regard all display pixels as initially white.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"137"Monocarp is playing a tower defense game. A level in the game can be represented as an OX axis, where each lattice point from $$$1$$$ to $$$n$$$ contains a tower in it.The tower in the $$$i$$$-th point has $$$c_i$$$ mana capacity and $$$r_i$$$ mana regeneration rate. In the beginning, before the $$$0$$$-th second, each tower has full mana. If, at the end of some second, the $$$i$$$-th tower has $$$x$$$ mana, then it becomes $$$\mathit{min}(x + r_i, c_i)$$$ mana for the next second.There are $$$q$$$ monsters spawning on a level. The $$$j$$$-th monster spawns at point $$$1$$$ at the beginning of $$$t_j$$$-th second, and it has $$$h_j$$$ health. Every monster is moving $$$1$$$ point per second in the direction of increasing coordinate.When a monster passes the tower, the tower deals $$$\mathit{min}(H, M)$$$ damage to it, where $$$H$$$ is the current health of the monster and $$$M$$$ is the current mana amount of the tower. This amount gets subtracted from both monster's health and tower's mana.Unfortunately, sometimes some monsters can pass all $$$n$$$ towers and remain alive. Monocarp wants to know what will be the total health of the monsters after they pass all towers.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"138"Alina has a bracket sequence $$$s$$$ of length $$$2n$$$, consisting of $$$n$$$ opening brackets '(' and $$$n$$$ closing brackets ')'. As she likes balance, she wants to turn this bracket sequence into a balanced bracket sequence.In one operation, she can reverse any substring of $$$s$$$.What's the smallest number of operations that she needs to turn $$$s$$$ into a balanced bracket sequence? It can be shown that it's always possible in at most $$$n$$$ operations.As a reminder, a sequence of brackets is called balanced if one can turn it into a valid math expression by adding characters + and 1. For example, sequences (())(), (), and (()(())) are balanced, while )(, ((), and (()))( are not.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"139"President of Berland has a very vast office-room, where, apart from him, work his subordinates. Each subordinate, as well as President himself, has his own desk of a unique colour. Each desk is rectangular, and its sides are parallel to the office walls. One day President decided to establish an assembly, of which all his deputies will be members. Unfortunately, he does not remember the exact amount of his deputies, but he remembers that the desk of each his deputy is adjacent to his own desk, that is to say, the two desks (President's and each deputy's) have a common side of a positive length.The office-room plan can be viewed as a matrix with n rows and m columns. Each cell of this matrix is either empty, or contains a part of a desk. An uppercase Latin letter stands for each desk colour. The «period» character («.») stands for an empty cell. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"140"This is a simplified version of the task Toy Train. These two versions differ only in the constraints. Hacks for this version are disabled.Alice received a set of Toy Train™ from Bob. It consists of one train and a connected railway network of $$$n$$$ stations, enumerated from $$$1$$$ through $$$n$$$. The train occupies one station at a time and travels around the network of stations in a circular manner. More precisely, the immediate station that the train will visit after station $$$i$$$ is station $$$i+1$$$ if $$$1 \leq i < n$$$ or station $$$1$$$ if $$$i = n$$$. It takes the train $$$1$$$ second to travel to its next station as described.Bob gave Alice a fun task before he left: to deliver $$$m$$$ candies that are initially at some stations to their independent destinations using the train. The candies are enumerated from $$$1$$$ through $$$m$$$. Candy $$$i$$$ ($$$1 \leq i \leq m$$$), now at station $$$a_i$$$, should be delivered to station $$$b_i$$$ ($$$a_i \neq b_i$$$).    The blue numbers on the candies correspond to $$$b_i$$$ values. The image corresponds to the $$$1$$$-st example. The train has infinite capacity, and it is possible to load off any number of candies at a station. However, only at most one candy can be loaded from a station onto the train before it leaves the station. You can choose any candy at this station. The time it takes to move the candies is negligible.Now, Alice wonders how much time is needed for the train to deliver all candies. Your task is to find, for each station, the minimum time the train would need to deliver all the candies were it to start from there.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"141"Polycarp is working on a new project called ""Polychat"". Following modern tendencies in IT, he decided, that this project should contain chat as well. To achieve this goal, Polycarp has spent several hours in front of his laptop and implemented a chat server that can process three types of commands:  Include a person to the chat ('Add' command).  Remove a person from the chat ('Remove' command).  Send a message from a person to all people, who are currently in the chat, including the one, who sends the message ('Send' command). Now Polycarp wants to find out the amount of outgoing traffic that the server will produce while processing a particular set of commands.Polycarp knows that chat server sends no traffic for 'Add' and 'Remove' commands. When 'Send' command is processed, server sends l bytes to each participant of the chat, where l is the length of the message.As Polycarp has no time, he is asking for your help in solving this problem.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"142"Berland shop sells $$$n$$$ kinds of juices. Each juice has its price $$$c_i$$$. Each juice includes some set of vitamins in it. There are three types of vitamins: vitamin ""A"", vitamin ""B"" and vitamin ""C"". Each juice can contain one, two or all three types of vitamins in it.Petya knows that he needs all three types of vitamins to stay healthy. What is the minimum total price of juices that Petya has to buy to obtain all three vitamins? Petya obtains some vitamin if he buys at least one juice containing it and drinks it.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"143"You are given a bracket sequence $$$s$$$ consisting of $$$n$$$ opening '(' and closing ')' brackets.A regular bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters '1' and '+' between the original characters of the sequence. For example, bracket sequences ""()()"", ""(())"" are regular (the resulting expressions are: ""(1)+(1)"", ""((1+1)+1)""), and "")("" and ""("" are not.You can change the type of some bracket $$$s_i$$$. It means that if $$$s_i = $$$ ')' then you can change it to '(' and vice versa.Your task is to calculate the number of positions $$$i$$$ such that if you change the type of the $$$i$$$-th bracket, then the resulting bracket sequence becomes regular.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"144"Currently Tiny is learning Computational Geometry. When trying to solve a problem called ""The Closest Pair Of Points In The Plane"", he found that a code which gave a wrong time complexity got Accepted instead of Time Limit Exceeded.The problem is the follows. Given n points in the plane, find a pair of points between which the distance is minimized. Distance between (x1, y1) and (x2, y2) is .The pseudo code of the unexpected code is as follows:input nfor i from 1 to n    input the i-th point's coordinates into p[i]sort array p[] by increasing of x coordinate first and increasing of y coordinate secondd=INF        //here INF is a number big enoughtot=0for i from 1 to n    for j from (i+1) to n        ++tot        if (p[j].x-p[i].x>=d) then break    //notice that ""break"" is only to be                                            //out of the loop ""for j""        d=min(d,distance(p[i],p[j]))output dHere, tot can be regarded as the running time of the code. Due to the fact that a computer can only run a limited number of operations per second, tot should not be more than k in order not to get Time Limit Exceeded.You are a great hacker. Would you please help Tiny generate a test data and let the code get Time Limit Exceeded?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"145"Barney lives in country USC (United States of Charzeh). USC has n cities numbered from 1 through n and n - 1 roads between them. Cities and roads of USC form a rooted tree (Barney's not sure why it is rooted). Root of the tree is the city number 1. Thus if one will start his journey from city 1, he can visit any city he wants by following roads.  Some girl has stolen Barney's heart, and Barney wants to find her. He starts looking for in the root of the tree and (since he is Barney Stinson not a random guy), he uses a random DFS to search in the cities. A pseudo code of this algorithm is as follows:let starting_time be an array of length ncurrent_time = 0dfs(v):	current_time = current_time + 1	starting_time[v] = current_time	shuffle children[v] randomly (each permutation with equal possibility)	// children[v] is vector of children cities of city v	for u in children[v]:		dfs(u)As told before, Barney will start his journey in the root of the tree (equivalent to call dfs(1)).Now Barney needs to pack a backpack and so he wants to know more about his upcoming journey: for every city i, Barney wants to know the expected value of starting_time[i]. He's a friend of Jon Snow and knows nothing, that's why he asked for your help.","['math', 'probabilities', 'trees']","[0, 0, 0, 1, 0, 1, 0, 1]"146"Suppose that you are in a campus and have to go for classes day by day. As you may see, when you hurry to a classroom, you surprisingly find that many seats there are already occupied. Today you and your friends went for class, and found out that some of the seats were occupied.The classroom contains $$$n$$$ rows of seats and there are $$$m$$$ seats in each row. Then the classroom can be represented as an $$$n \times m$$$ matrix. The character '.' represents an empty seat, while '*' means that the seat is occupied. You need to find $$$k$$$ consecutive empty seats in the same row or column and arrange those seats for you and your friends. Your task is to find the number of ways to arrange the seats. Two ways are considered different if sets of places that students occupy differs.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"147"Students went into a class to write a test and sat in some way. The teacher thought: ""Probably they sat in this order to copy works of each other. I need to rearrange them in such a way that students that were neighbors are not neighbors in a new seating.""The class can be represented as a matrix with n rows and m columns with a student in each cell. Two students are neighbors if cells in which they sit have a common side.Let's enumerate students from 1 to n·m in order of rows. So a student who initially sits in the cell in row i and column j has a number (i - 1)·m + j. You have to find a matrix with n rows and m columns in which all numbers from 1 to n·m appear exactly once and adjacent numbers in the original matrix are not adjacent in it, or determine that there is no such matrix.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"148"We are given a rooted tree consisting of $$$n$$$ vertices numbered from $$$1$$$ to $$$n$$$. The root of the tree is the vertex $$$1$$$ and the parent of the vertex $$$v$$$ is $$$p_v$$$.There is a number written on each vertex, initially all numbers are equal to $$$0$$$. Let's denote the number written on the vertex $$$v$$$ as $$$a_v$$$.For each $$$v$$$, we want $$$a_v$$$ to be between $$$l_v$$$ and $$$r_v$$$ $$$(l_v \leq a_v \leq r_v)$$$.In a single operation we do the following:   Choose some vertex $$$v$$$. Let $$$b_1, b_2, \ldots, b_k$$$ be vertices on the path from the vertex $$$1$$$ to vertex $$$v$$$ (meaning $$$b_1 = 1$$$, $$$b_k = v$$$ and $$$b_i = p_{b_{i + 1}}$$$). Choose a non-decreasing array $$$c$$$ of length $$$k$$$ of nonnegative integers: $$$0 \leq c_1 \leq c_2 \leq \ldots \leq c_k$$$. For each $$$i$$$ $$$(1 \leq i \leq k)$$$, increase $$$a_{b_i}$$$ by $$$c_i$$$. What's the minimum number of operations needed to achieve our goal?",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"149"You have a team of N people. For a particular task, you can pick any non-empty subset of people. The cost of having x people for the task is xk. Output the sum of costs over all non-empty subsets of people.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"150"Two pirates Polycarpus and Vasily play a very interesting game. They have n chests with coins, the chests are numbered with integers from 1 to n. Chest number i has ai coins. Polycarpus and Vasily move in turns. Polycarpus moves first. During a move a player is allowed to choose a positive integer x (2·x + 1 ≤ n) and take a coin from each chest with numbers x, 2·x, 2·x + 1. It may turn out that some chest has no coins, in this case the player doesn't take a coin from this chest. The game finishes when all chests get emptied.Polycarpus isn't a greedy scrooge. Polycarpys is a lazy slob. So he wonders in what minimum number of moves the game can finish. Help Polycarpus, determine the minimum number of moves in which the game can finish. Note that Polycarpus counts not only his moves, he also counts Vasily's moves.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"151"While Duff was resting in the beach, she accidentally found a strange array b0, b1, ..., bl - 1 consisting of l positive integers. This array was strange because it was extremely long, but there was another (maybe shorter) array, a0, ..., an - 1 that b can be build from a with formula: bi = ai mod n where a mod b denoted the remainder of dividing a by b.  Duff is so curious, she wants to know the number of subsequences of b like bi1, bi2, ..., bix (0 ≤ i1 < i2 < ... < ix < l), such that:   1 ≤ x ≤ k  For each 1 ≤ j ≤ x - 1,   For each 1 ≤ j ≤ x - 1, bij ≤ bij + 1. i.e this subsequence is non-decreasing. Since this number can be very large, she want to know it modulo 109 + 7.Duff is not a programmer, and Malek is unavailable at the moment. So she asked for your help. Please tell her this number.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"152"Slime and his $$$n$$$ friends are at a party. Slime has designed a game for his friends to play.At the beginning of the game, the $$$i$$$-th player has $$$a_i$$$ biscuits. At each second, Slime will choose a biscuit randomly uniformly among all $$$a_1 + a_2 + \ldots + a_n$$$ biscuits, and the owner of this biscuit will give it to a random uniform player among $$$n-1$$$ players except himself. The game stops when one person will have all the biscuits.As the host of the party, Slime wants to know the expected value of the time that the game will last, to hold the next activity on time.For convenience, as the answer can be represented as a rational number $$$\frac{p}{q}$$$ for coprime $$$p$$$ and $$$q$$$, you need to find the value of $$$(p \cdot q^{-1})\mod 998\,244\,353$$$. You can prove that $$$q\mod 998\,244\,353 \neq 0$$$.","['math', 'probabilities']","[0, 0, 0, 1, 0, 1, 0, 0]"153"Due to the increase in the number of students of Berland State University it was decided to equip a new computer room. You were given the task of buying mouses, and you have to spend as little as possible. After all, the country is in crisis!The computers bought for the room were different. Some of them had only USB ports, some — only PS/2 ports, and some had both options.You have found a price list of a certain computer shop. In it, for m mouses it is specified the cost and the type of the port that is required to plug the mouse in (USB or PS/2). Each mouse from the list can be bought at most once.You want to buy some set of mouses from the given price list in such a way so that you maximize the number of computers equipped with mouses (it is not guaranteed that you will be able to equip all of the computers), and in case of equality of this value you want to minimize the total cost of mouses you will buy.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"154"Suppose you had an array $$$A$$$ of $$$n$$$ elements, each of which is $$$0$$$ or $$$1$$$.Let us define a function $$$f(k,A)$$$ which returns another array $$$B$$$, the result of sorting the first $$$k$$$ elements of $$$A$$$ in non-decreasing order. For example, $$$f(4,[0,1,1,0,0,1,0]) = [0,0,1,1,0,1,0]$$$. Note that the first $$$4$$$ elements were sorted.Now consider the arrays $$$B_1, B_2,\ldots, B_n$$$ generated by $$$f(1,A), f(2,A),\ldots,f(n,A)$$$. Let $$$C$$$ be the array obtained by taking the element-wise sum of $$$B_1, B_2,\ldots, B_n$$$.For example, let $$$A=[0,1,0,1]$$$. Then we have $$$B_1=[0,1,0,1]$$$, $$$B_2=[0,1,0,1]$$$, $$$B_3=[0,0,1,1]$$$, $$$B_4=[0,0,1,1]$$$. Then $$$C=B_1+B_2+B_3+B_4=[0,1,0,1]+[0,1,0,1]+[0,0,1,1]+[0,0,1,1]=[0,2,2,4]$$$.You are given $$$C$$$. Determine a binary array $$$A$$$ that would give $$$C$$$ when processed as above. It is guaranteed that an array $$$A$$$ exists for given $$$C$$$ in the input. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"155"In Aramic language words can only represent objects.Words in Aramic have special properties:   A word is a root if it does not contain the same letter more than once.  A root and all its permutations represent the same object.  The root $$$x$$$ of a word $$$y$$$ is the word that contains all letters that appear in $$$y$$$ in a way that each letter appears once. For example, the root of ""aaaa"", ""aa"", ""aaa"" is ""a"", the root of ""aabb"", ""bab"", ""baabb"", ""ab"" is ""ab"".  Any word in Aramic represents the same object as its root. You have an ancient script in Aramic. What is the number of different objects mentioned in the script?",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"156"  William is a huge fan of planning ahead. That is why he starts his morning routine by creating a nested list of upcoming errands.A valid nested list is any list which can be created from a list with one item ""1"" by applying some operations. Each operation inserts a new item into the list, on a new line, just after one of existing items $$$a_1 \,.\, a_2 \,.\, a_3 \,.\, \,\cdots\, \,.\,a_k$$$ and can be one of two types:   Add an item $$$a_1 \,.\, a_2 \,.\, a_3 \,.\, \cdots \,.\, a_k \,.\, 1$$$ (starting a list of a deeper level), or  Add an item $$$a_1 \,.\, a_2 \,.\, a_3 \,.\, \cdots \,.\, (a_k + 1)$$$ (continuing the current level).  Operation can only be applied if the list does not contain two identical items afterwards. And also, if we consider every item as a sequence of numbers, then the sequence of items should always remain increasing in lexicographical order. Examples of valid and invalid lists that are shown in the picture can found in the ""Notes"" section.When William decided to save a Word document with the list of his errands he accidentally hit a completely different keyboard shortcut from the ""Ctrl-S"" he wanted to hit. It's not known exactly what shortcut he pressed but after triggering it all items in the list were replaced by a single number: the last number originally written in the item number.William wants you to help him restore a fitting original nested list.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"157"Martians are actively engaged in interplanetary trade. Olymp City, the Martian city known for its spaceport, has become a place where goods from all the corners of our Galaxy come. To deliver even more freight from faraway planets, Martians need fast spaceships.A group of scientists conducts experiments to build a fast engine for the new spaceship. In the current experiment, there are $$$n$$$ elementary particles, the $$$i$$$-th of them has type $$$a_i$$$.Denote a subsegment of the particle sequence ($$$a_1, a_2, \dots, a_n$$$) as a sequence ($$$a_l, a_{l+1}, \dots, a_r$$$) for some left bound $$$l$$$ and right bound $$$r$$$ ($$$1 \le l \le r \le n$$$). For instance, the sequence $$$(1\ 4\ 2\ 8\ 5\ 7)$$$ for $$$l=2$$$ and $$$r=4$$$ has the sequence $$$(4\ 2\ 8)$$$ as a subsegment. Two subsegments are considered different if at least one bound of those subsegments differs.Note that the subsegments can be equal as sequences but still considered different. For example, consider the sequence $$$(1\ 1\ 1\ 1\ 1)$$$ and two of its subsegments: one with $$$l=1$$$ and $$$r=3$$$ and another with $$$l=2$$$ and $$$r=4$$$. Both subsegments are equal to $$$(1\ 1\ 1)$$$, but still considered different, as their left and right bounds differ.The scientists want to conduct a reaction to get two different subsegments of the same length. Denote this length $$$k$$$. The resulting pair of subsegments must be harmonious, i. e. for some $$$i$$$ ($$$1 \le i \le k$$$) it must be true that the types of particles on the $$$i$$$-th position are the same for these two subsegments. For example, the pair $$$(1\ 7\ 3)$$$ and $$$(4\ 7\ 8)$$$ is harmonious, as both subsegments have $$$7$$$ on the second position. The pair $$$(1\ 2\ 3)$$$ and $$$(3\ 1\ 2)$$$ is not harmonious.The longer are harmonious subsegments, the more chances for the scientists to design a fast engine. So, they asked you to calculate the maximal possible length of harmonious pair made of different subsegments.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"158"This is an interactive problem.We have hidden an integer $$$1 \le X \le 10^{9}$$$. You don't have to guess this number. You have to find the number of divisors of this number, and you don't even have to find the exact number: your answer will be considered correct if its absolute error is not greater than 7 or its relative error is not greater than $$$0.5$$$. More formally, let your answer be $$$ans$$$ and the number of divisors of $$$X$$$ be $$$d$$$, then your answer will be considered correct if at least one of the two following conditions is true: $$$| ans - d | \le 7$$$; $$$\frac{1}{2} \le \frac{ans}{d} \le 2$$$.You can make at most $$$22$$$ queries. One query consists of one integer $$$1 \le Q \le 10^{18}$$$. In response, you will get $$$gcd(X, Q)$$$ — the greatest common divisor of $$$X$$$ and $$$Q$$$.The number $$$X$$$ is fixed before all queries. In other words, interactor is not adaptive.Let's call the process of guessing the number of divisors of number $$$X$$$ a game. In one test you will have to play $$$T$$$ independent games, that is, guess the number of divisors $$$T$$$ times for $$$T$$$ independent values of $$$X$$$.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"159"Stephen Queen wants to write a story. He is a very unusual writer, he uses only letters 'a', 'b', 'c', 'd' and 'e'!To compose a story, Stephen wrote out $$$n$$$ words consisting of the first $$$5$$$ lowercase letters of the Latin alphabet. He wants to select the maximum number of words to make an interesting story.Let a story be a sequence of words that are not necessarily different. A story is called interesting if there exists a letter which occurs among all words of the story more times than all other letters together.For example, the story consisting of three words ""bac"", ""aaada"", ""e"" is interesting (the letter 'a' occurs $$$5$$$ times, all other letters occur $$$4$$$ times in total). But the story consisting of two words ""aba"", ""abcde"" is not (no such letter that it occurs more than all other letters in total).You are given a sequence of $$$n$$$ words consisting of letters 'a', 'b', 'c', 'd' and 'e'. Your task is to choose the maximum number of them to make an interesting story. If there's no way to make a non-empty story, output $$$0$$$.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"160"There is a bus stop near the university. The lessons are over, and n students come to the stop. The i-th student will appear at the bus stop at time ti (all ti's are distinct).We shall assume that the stop is located on the coordinate axis Ox, at point x = 0, and the bus goes along the ray Ox, that is, towards the positive direction of the coordinate axis, and back. The i-th student needs to get to the point with coordinate xi (xi > 0).The bus moves by the following algorithm. Initially it is at point 0. The students consistently come to the stop and get on it. The bus has a seating capacity which is equal to m passengers. At the moment when m students get on the bus, it starts moving in the positive direction of the coordinate axis. Also it starts moving when the last (n-th) student gets on the bus. The bus is moving at a speed of 1 unit of distance per 1 unit of time, i.e. it covers distance y in time y.Every time the bus passes the point at which at least one student needs to get off, it stops and these students get off the bus. The students need 1 + [k / 2] units of time to get off the bus, where k is the number of students who leave at this point. Expression [k / 2] denotes rounded down k / 2. As soon as the last student leaves the bus, the bus turns around and goes back to the point x = 0. It doesn't make any stops until it reaches the point. At the given point the bus fills with students once more, and everything is repeated.If students come to the stop when there's no bus, they form a line (queue) and get on the bus in the order in which they came. Any number of students get on the bus in negligible time, you should assume that it doesn't take any time. Any other actions also take no time. The bus has no other passengers apart from the students.Write a program that will determine for each student the time when he got off the bus. The moment a student got off the bus is the moment the bus stopped at the student's destination stop (despite the fact that the group of students need some time to get off).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"161"You are given an integer $$$n$$$.You can perform any of the following operations with this number an arbitrary (possibly, zero) number of times:   Replace $$$n$$$ with $$$\frac{n}{2}$$$ if $$$n$$$ is divisible by $$$2$$$;  Replace $$$n$$$ with $$$\frac{2n}{3}$$$ if $$$n$$$ is divisible by $$$3$$$;  Replace $$$n$$$ with $$$\frac{4n}{5}$$$ if $$$n$$$ is divisible by $$$5$$$. For example, you can replace $$$30$$$ with $$$15$$$ using the first operation, with $$$20$$$ using the second operation or with $$$24$$$ using the third operation.Your task is to find the minimum number of moves required to obtain $$$1$$$ from $$$n$$$ or say that it is impossible to do it.You have to answer $$$q$$$ independent queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"162"You are given three strings $$$a$$$, $$$b$$$ and $$$c$$$ of the same length $$$n$$$. The strings consist of lowercase English letters only. The $$$i$$$-th letter of $$$a$$$ is $$$a_i$$$, the $$$i$$$-th letter of $$$b$$$ is $$$b_i$$$, the $$$i$$$-th letter of $$$c$$$ is $$$c_i$$$.For every $$$i$$$ ($$$1 \leq i \leq n$$$) you must swap (i.e. exchange) $$$c_i$$$ with either $$$a_i$$$ or $$$b_i$$$. So in total you'll perform exactly $$$n$$$ swap operations, each of them either $$$c_i \leftrightarrow a_i$$$ or $$$c_i \leftrightarrow b_i$$$ ($$$i$$$ iterates over all integers between $$$1$$$ and $$$n$$$, inclusive).For example, if $$$a$$$ is ""code"", $$$b$$$ is ""true"", and $$$c$$$ is ""help"", you can make $$$c$$$ equal to ""crue"" taking the $$$1$$$-st and the $$$4$$$-th letters from $$$a$$$ and the others from $$$b$$$. In this way $$$a$$$ becomes ""hodp"" and $$$b$$$ becomes ""tele"".Is it possible that after these swaps the string $$$a$$$ becomes exactly the same as the string $$$b$$$?",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"163"Fox Ciel is participating in a party in Prime Kingdom. There are n foxes there (include Fox Ciel). The i-th fox is ai years old.They will have dinner around some round tables. You want to distribute foxes such that:  Each fox is sitting at some table.  Each table has at least 3 foxes sitting around it.  The sum of ages of any two adjacent foxes around each table should be a prime number. If k foxes f1, f2, ..., fk are sitting around table in clockwise order, then for 1 ≤ i ≤ k - 1: fi and fi + 1 are adjacent, and f1 and fk are also adjacent.If it is possible to distribute the foxes in the desired manner, find out a way to do that.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"164"On the math lesson a teacher asked each pupil to come up with his own lucky numbers. As a fan of number theory Peter chose prime numbers. Bob was more original. He said that number t is his lucky number, if it can be represented as: t = a2 + b2,  where a, b are arbitrary positive integers.Now, the boys decided to find out how many days of the interval [l, r] (l ≤ r) are suitable for pair programming. They decided that the day i (l ≤ i ≤ r) is suitable for pair programming if and only if the number i is lucky for Peter and lucky for Bob at the same time. Help the boys to find the number of such days.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"165"There are two decks of cards lying on the table in front of you, some cards in these decks lay face up, some of them lay face down. You want to merge them into one deck in which each card is face down. You're going to do it in two stages.The first stage is to merge the two decks in such a way that the relative order of the cards from the same deck doesn't change. That is, for any two different cards i and j in one deck, if card i lies above card j, then after the merge card i must also be above card j.The second stage is performed on the deck that resulted from the first stage. At this stage, the executed operation is the turning operation. In one turn you can take a few of the top cards, turn all of them, and put them back. Thus, each of the taken cards gets turned and the order of these cards is reversed. That is, the card that was on the bottom before the turn, will be on top after it.Your task is to make sure that all the cards are lying face down. Find such an order of merging cards in the first stage and the sequence of turning operations in the second stage, that make all the cards lie face down, and the number of turns is minimum.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"166"One day Alex decided to remember childhood when computers were not too powerful and lots of people played only default games. Alex enjoyed playing Minesweeper that time. He imagined that he saved world from bombs planted by terrorists, but he rarely won.Alex has grown up since then, so he easily wins the most difficult levels. This quickly bored him, and he thought: what if the computer gave him invalid fields in the childhood and Alex could not win because of it?He needs your help to check it.A Minesweeper field is a rectangle $$$n \times m$$$, where each cell is either empty, or contains a digit from $$$1$$$ to $$$8$$$, or a bomb. The field is valid if for each cell:   if there is a digit $$$k$$$ in the cell, then exactly $$$k$$$ neighboring cells have bombs.  if the cell is empty, then all neighboring cells have no bombs. Two cells are neighbors if they have a common side or a corner (i. e. a cell has at most $$$8$$$ neighboring cells).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"167"A sky scraper with 1000 floors has been built in the city of N. It has modern superfast elevators to help to travel from one floor to another. Each elevator has two doors, the front one and the back one. If one goes in through the front door, he goes out through the back one and vice versa. The elevator has two rails numbered with numbers 1 and 2. Rail 1 is located to the left of the entrance to the front door (or correspondingly, to the right of the entrance to the back door). Rail 2 is located opposite it, to the right of the entrance to the front door and to the left of the entrance to the back door. We know that each person in the city of N holds at a rail with the strongest hand. One day a VIP person visited the city and of course, he took a look at the skyscraper and took a ride in the elevator. We know the door through which he entered and the rail he was holding at. Now we need to determine as soon as possible whether he is left-handed or right-handed.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"168"The only difference between easy and hard versions is constraints.Nauuo is a girl who loves random picture websites.One day she made a random picture website by herself which includes $$$n$$$ pictures.When Nauuo visits the website, she sees exactly one picture. The website does not display each picture with equal probability. The $$$i$$$-th picture has a non-negative weight $$$w_i$$$, and the probability of the $$$i$$$-th picture being displayed is $$$\frac{w_i}{\sum_{j=1}^nw_j}$$$. That is to say, the probability of a picture to be displayed is proportional to its weight.However, Nauuo discovered that some pictures she does not like were displayed too often. To solve this problem, she came up with a great idea: when she saw a picture she likes, she would add $$$1$$$ to its weight; otherwise, she would subtract $$$1$$$ from its weight.Nauuo will visit the website $$$m$$$ times. She wants to know the expected weight of each picture after all the $$$m$$$ visits modulo $$$998244353$$$. Can you help her?The expected weight of the $$$i$$$-th picture can be denoted by $$$\frac {q_i} {p_i}$$$ where $$$\gcd(p_i,q_i)=1$$$, you need to print an integer $$$r_i$$$ satisfying $$$0\le r_i<998244353$$$ and $$$r_i\cdot p_i\equiv q_i\pmod{998244353}$$$. It can be proved that such $$$r_i$$$ exists and is unique.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"169"It is the middle of 2018 and Maria Stepanovna, who lives outside Krasnokamensk (a town in Zabaikalsky region), wants to rent three displays to highlight an important problem.There are $$$n$$$ displays placed along a road, and the $$$i$$$-th of them can display a text with font size $$$s_i$$$ only. Maria Stepanovna wants to rent such three displays with indices $$$i < j < k$$$ that the font size increases if you move along the road in a particular direction. Namely, the condition $$$s_i < s_j < s_k$$$ should be held.The rent cost is for the $$$i$$$-th display is $$$c_i$$$. Please determine the smallest cost Maria Stepanovna should pay.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"170"In the spirit of the holidays, Saitama has given Genos two grid paths of length n (a weird gift even by Saitama's standards). A grid path is an ordered sequence of neighbouring squares in an infinite grid. Two squares are neighbouring if they share a side.One example of a grid path is (0, 0) → (0, 1) → (0, 2) → (1, 2) → (1, 1) → (0, 1) → ( - 1, 1). Note that squares in this sequence might be repeated, i.e. path has self intersections.Movement within a grid path is restricted to adjacent squares within the sequence. That is, from the i-th square, one can only move to the (i - 1)-th or (i + 1)-th squares of this path. Note that there is only a single valid move from the first and last squares of a grid path. Also note, that even if there is some j-th square of the path that coincides with the i-th square, only moves to (i - 1)-th and (i + 1)-th squares are available. For example, from the second square in the above sequence, one can only move to either the first or third squares.To ensure that movement is not ambiguous, the two grid paths will not have an alternating sequence of three squares. For example, a contiguous subsequence (0, 0) → (0, 1) → (0, 0) cannot occur in a valid grid path.One marble is placed on the first square of each grid path. Genos wants to get both marbles to the last square of each grid path. However, there is a catch. Whenever he moves one marble, the other marble will copy its movement if possible. For instance, if one marble moves east, then the other marble will try and move east as well. By try, we mean if moving east is a valid move, then the marble will move east.Moving north increases the second coordinate by 1, while moving south decreases it by 1. Similarly, moving east increases first coordinate by 1, while moving west decreases it.Given these two valid grid paths, Genos wants to know if it is possible to move both marbles to the ends of their respective paths. That is, if it is possible to move the marbles such that both marbles rest on the last square of their respective paths.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"171"Ivan is collecting coins. There are only $$$N$$$ different collectible coins, Ivan has $$$K$$$ of them. He will be celebrating his birthday soon, so all his $$$M$$$ freinds decided to gift him coins. They all agreed to three terms:  Everyone must gift as many coins as others. All coins given to Ivan must be different. Not less than $$$L$$$ coins from gifts altogether, must be new in Ivan's collection.But his friends don't know which coins have Ivan already got in his collection. They don't want to spend money so they want to buy minimum quantity of coins, that satisfy all terms, irrespective of the Ivan's collection. Help them to find this minimum number of coins or define it's not possible to meet all the terms.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"172"Caisa is going to have a party and he needs to buy the ingredients for a big chocolate cake. For that he is going to the biggest supermarket in town.Unfortunately, he has just s dollars for sugar. But that's not a reason to be sad, because there are n types of sugar in the supermarket, maybe he able to buy one. But that's not all. The supermarket has very unusual exchange politics: instead of cents the sellers give sweets to a buyer as a change. Of course, the number of given sweets always doesn't exceed 99, because each seller maximizes the number of dollars in the change (100 cents can be replaced with a dollar).Caisa wants to buy only one type of sugar, also he wants to maximize the number of sweets in the change. What is the maximum number of sweets he can get? Note, that Caisa doesn't want to minimize the cost of the sugar, he only wants to get maximum number of sweets as change. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"173"This is a hard version of the problem. The only difference between an easy and a hard version is in the number of queries.Polycarp grew a tree from $$$n$$$ vertices. We remind you that a tree of $$$n$$$ vertices is an undirected connected graph of $$$n$$$ vertices and $$$n-1$$$ edges that does not contain cycles.He calls a set of vertices passable if there is such a path in the tree that passes through each vertex of this set without passing through any edge twice. The path can visit other vertices (not from this set).In other words, a set of vertices is called passable if there is a simple path that passes through all the vertices of this set (and possibly some other).For example, for a tree below sets $$$\{3, 2, 5\}$$$, $$$\{1, 5, 4\}$$$, $$$\{1, 4\}$$$ are passable, and $$$\{1, 3, 5\}$$$, $$$\{1, 2, 3, 4, 5\}$$$ are not.  Polycarp asks you to answer $$$q$$$ queries. Each query is a set of vertices. For each query, you need to determine whether the corresponding set of vertices is passable.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"174"You are given a directed acyclic graph, consisting of $$$n$$$ vertices and $$$m$$$ edges. The vertices are numbered from $$$1$$$ to $$$n$$$. There are no multiple edges and self-loops.Let $$$\mathit{in}_v$$$ be the number of incoming edges (indegree) and $$$\mathit{out}_v$$$ be the number of outgoing edges (outdegree) of vertex $$$v$$$.You are asked to remove some edges from the graph. Let the new degrees be $$$\mathit{in'}_v$$$ and $$$\mathit{out'}_v$$$.You are only allowed to remove the edges if the following conditions hold for every vertex $$$v$$$:   $$$\mathit{in'}_v < \mathit{in}_v$$$ or $$$\mathit{in'}_v = \mathit{in}_v = 0$$$;  $$$\mathit{out'}_v < \mathit{out}_v$$$ or $$$\mathit{out'}_v = \mathit{out}_v = 0$$$. Let's call a set of vertices $$$S$$$ cute if for each pair of vertices $$$v$$$ and $$$u$$$ ($$$v \neq u$$$) such that $$$v \in S$$$ and $$$u \in S$$$, there exists a path either from $$$v$$$ to $$$u$$$ or from $$$u$$$ to $$$v$$$ over the non-removed edges.What is the maximum possible size of a cute set $$$S$$$ after you remove some edges from the graph and both indegrees and outdegrees of all vertices either decrease or remain equal to $$$0$$$?",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"175"Masha meets a new friend and learns his phone number — $$$s$$$. She wants to remember it as soon as possible. The phone number — is a string of length $$$m$$$ that consists of digits from $$$0$$$ to $$$9$$$. The phone number may start with 0.Masha already knows $$$n$$$ phone numbers (all numbers have the same length $$$m$$$). It will be easier for her to remember a new number if the $$$s$$$ is represented as segments of numbers she already knows. Each such segment must be of length at least $$$2$$$, otherwise there will be too many segments and Masha will get confused.For example, Masha needs to remember the number: $$$s = $$$ '12345678' and she already knows $$$n = 4$$$ numbers: '12340219', '20215601', '56782022', '12300678'. You can represent $$$s$$$ as a $$$3$$$ segment: '1234' of number one, '56' of number two, and '78' of number three. There are other ways to represent $$$s$$$.Masha asks you for help, she asks you to break the string $$$s$$$ into segments of length $$$2$$$ or more of the numbers she already knows. If there are several possible answers, print any of them.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"176"Polycarp loves geometric progressions — he collects them. However, as such progressions occur very rarely, he also loves the sequences of numbers where it is enough to delete a single element to get a geometric progression.In this task we shall define geometric progressions as finite sequences of numbers a1, a2, ..., ak, where ai = c·bi - 1 for some real numbers c and b. For example, the sequences [2, -4, 8], [0, 0, 0, 0], [199] are geometric progressions and [0, 1, 2, 3] is not.Recently Polycarp has found a sequence and he can't classify it. Help him to do it. Determine whether it is a geometric progression. If it is not, check if it can become a geometric progression if an element is deleted from it.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"177You are given array a with n elements and the number m. Consider some subsequence of a and the value of least common multiple (LCM) of its elements. Denote LCM as l. Find any longest subsequence of a with the value l ≤ m.A subsequence of a is an array we can get by erasing some elements of a. It is allowed to erase zero or all elements.The LCM of an empty array equals 1.,"['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"178"You are an ambitious king who wants to be the Emperor of The Reals. But to do that, you must first become Emperor of The Integers.Consider a number axis. The capital of your empire is initially at $$$0$$$. There are $$$n$$$ unconquered kingdoms at positions $$$0<x_1<x_2<\ldots<x_n$$$. You want to conquer all other kingdoms.There are two actions available to you:   You can change the location of your capital (let its current position be $$$c_1$$$) to any other conquered kingdom (let its position be $$$c_2$$$) at a cost of $$$a\cdot |c_1-c_2|$$$.  From the current capital (let its current position be $$$c_1$$$) you can conquer an unconquered kingdom (let its position be $$$c_2$$$) at a cost of $$$b\cdot |c_1-c_2|$$$. You cannot conquer a kingdom if there is an unconquered kingdom between the target and your capital. Note that you cannot place the capital at a point without a kingdom. In other words, at any point, your capital can only be at $$$0$$$ or one of $$$x_1,x_2,\ldots,x_n$$$. Also note that conquering a kingdom does not change the position of your capital.Find the minimum total cost to conquer all kingdoms. Your capital can be anywhere at the end.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"179"Let's call an array of non-negative integers $$$a_1, a_2, \ldots, a_n$$$ a $$$k$$$-extension for some non-negative integer $$$k$$$ if for all possible pairs of indices $$$1 \leq i, j \leq n$$$ the inequality $$$k \cdot |i - j| \leq min(a_i, a_j)$$$ is satisfied. The expansion coefficient of the array $$$a$$$ is the maximal integer $$$k$$$ such that the array $$$a$$$ is a $$$k$$$-extension. Any array is a 0-expansion, so the expansion coefficient always exists.You are given an array of non-negative integers $$$a_1, a_2, \ldots, a_n$$$. Find its expansion coefficient.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"180"There were n groups of students which came to write a training contest. A group is either one person who can write the contest with anyone else, or two people who want to write the contest in the same team.The coach decided to form teams of exactly three people for this training. Determine the maximum number of teams of three people he can form. It is possible that he can't use all groups to form teams. For groups of two, either both students should write the contest, or both should not. If two students from a group of two will write the contest, they should be in the same team.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"181"An arithmetic progression is such a non-empty sequence of numbers where the difference between any two successive numbers is constant. This constant number is called common difference. For example, the sequence 3, 7, 11, 15 is an arithmetic progression. The definition implies that any sequences whose length equals 1 or 2 are arithmetic and all sequences whose length equals 0 are non-arithmetic.You are given a sequence of different integers a1, a2, ..., an. You should either split it into two arithmetic progressions or find out that the operation is impossible to perform. Splitting assigns each member of the given sequence to one of two progressions, but the relative order of numbers does not change. Splitting is an inverse operation to merging.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"182"Nezzar loves the game osu!.osu! is played on beatmaps, which can be seen as an array consisting of distinct points on a plane. A beatmap is called nice if for any three consecutive points $$$A,B,C$$$ listed in order, the angle between these three points, centered at $$$B$$$, is strictly less than $$$90$$$ degrees.  Points $$$A,B,C$$$ on the left have angle less than $$$90$$$ degrees, so they can be three consecutive points of a nice beatmap; Points $$$A',B',C'$$$ on the right have angle greater or equal to $$$90$$$ degrees, so they cannot be three consecutive points of a nice beatmap. Now Nezzar has a beatmap of $$$n$$$ distinct points $$$A_1,A_2,\ldots,A_n$$$. Nezzar would like to reorder these $$$n$$$ points so that the resulting beatmap is nice.Formally, you are required to find a permutation $$$p_1,p_2,\ldots,p_n$$$ of integers from $$$1$$$ to $$$n$$$, such that beatmap $$$A_{p_1},A_{p_2},\ldots,A_{p_n}$$$ is nice. If it is impossible, you should determine it.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"183"You are given a tree with $$$n$$$ vertices. You are allowed to modify the structure of the tree through the following multi-step operation:  Choose three vertices $$$a$$$, $$$b$$$, and $$$c$$$ such that $$$b$$$ is adjacent to both $$$a$$$ and $$$c$$$.  For every vertex $$$d$$$ other than $$$b$$$ that is adjacent to $$$a$$$, remove the edge connecting $$$d$$$ and $$$a$$$ and add the edge connecting $$$d$$$ and $$$c$$$.  Delete the edge connecting $$$a$$$ and $$$b$$$ and add the edge connecting $$$a$$$ and $$$c$$$. As an example, consider the following tree:  The following diagram illustrates the sequence of steps that happen when we apply an operation to vertices $$$2$$$, $$$4$$$, and $$$5$$$:  It can be proven that after each operation, the resulting graph is still a tree.Find the minimum number of operations that must be performed to transform the tree into a star. A star is a tree with one vertex of degree $$$n - 1$$$, called its center, and $$$n - 1$$$ vertices of degree $$$1$$$.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"184"One popular website developed an unusual username editing procedure. One can change the username only by deleting some characters from it: to change the current name s, a user can pick number p and character c and delete the p-th occurrence of character c from the name. After the user changed his name, he can't undo the change.For example, one can change name ""arca"" by removing the second occurrence of character ""a"" to get ""arc"". Polycarpus learned that some user initially registered under nickname t, where t is a concatenation of k copies of string s. Also, Polycarpus knows the sequence of this user's name changes. Help Polycarpus figure out the user's final name.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"185"You are given a set Y of n distinct positive integers y1, y2, ..., yn.Set X of n distinct positive integers x1, x2, ..., xn is said to generate set Y if one can transform X to Y by applying some number of the following two operation to integers in X:  Take any integer xi and multiply it by two, i.e. replace xi with 2·xi.  Take any integer xi, multiply it by two and add one, i.e. replace xi with 2·xi + 1. Note that integers in X are not required to be distinct after each operation.Two sets of distinct integers X and Y are equal if they are equal as sets. In other words, if we write elements of the sets in the array in the increasing order, these arrays would be equal.Note, that any set of integers (or its permutation) generates itself.You are given a set Y and have to find a set X that generates Y and the maximum element of X is mininum possible.","['strings', 'trees']","[0, 0, 0, 0, 0, 0, 1, 1]"186"The country Treeland consists of n cities, some pairs of them are connected with unidirectional roads. Overall there are n - 1 roads in the country. We know that if we don't take the direction of the roads into consideration, we can get from any city to any other one.The council of the elders has recently decided to choose the capital of Treeland. Of course it should be a city of this country. The council is supposed to meet in the capital and regularly move from the capital to other cities (at this stage nobody is thinking about getting back to the capital from these cities). For that reason if city a is chosen a capital, then all roads must be oriented so that if we move along them, we can get from city a to any other city. For that some roads may have to be inversed.Help the elders to choose the capital so that they have to inverse the minimum number of roads in the country.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"187"Student Valera is an undergraduate student at the University. His end of term exams are approaching and he is to pass exactly n exams. Valera is a smart guy, so he will be able to pass any exam he takes on his first try. Besides, he can take several exams on one day, and in any order.According to the schedule, a student can take the exam for the i-th subject on the day number ai. However, Valera has made an arrangement with each teacher and the teacher of the i-th subject allowed him to take an exam before the schedule time on day bi (bi < ai). Thus, Valera can take an exam for the i-th subject either on day ai, or on day bi. All the teachers put the record of the exam in the student's record book on the day of the actual exam and write down the date of the mark as number ai.Valera believes that it would be rather strange if the entries in the record book did not go in the order of non-decreasing date. Therefore Valera asks you to help him. Find the minimum possible value of the day when Valera can take the final exam if he takes exams so that all the records in his record book go in the order of non-decreasing date.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"188"Petya is a beginner programmer. He has already mastered the basics of the C++ language and moved on to learning algorithms. The first algorithm he encountered was insertion sort. Petya has already written the code that implements this algorithm and sorts the given integer zero-indexed array a of size n in the non-decreasing order. for (int i = 1; i < n; i = i + 1){   int j = i;    while (j > 0 && a[j] < a[j - 1])   {      swap(a[j], a[j - 1]); // swap elements a[j] and a[j - 1]      j = j - 1;   }}Petya uses this algorithm only for sorting of arrays that are permutations of numbers from 0 to n - 1. He has already chosen the permutation he wants to sort but he first decided to swap some two of its elements. Petya wants to choose these elements in such a way that the number of times the sorting executes function swap, was minimum. Help Petya find out the number of ways in which he can make the swap and fulfill this requirement.It is guaranteed that it's always possible to swap two elements of the input permutation in such a way that the number of swap function calls decreases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"189"Watto, the owner of a spare parts store, has recently got an order for the mechanism that can process strings in a certain way. Initially the memory of the mechanism is filled with n strings. Then the mechanism should be able to process queries of the following type: ""Given string s, determine if the memory of the mechanism contains string t that consists of the same number of characters as s and differs from s in exactly one position"".Watto has already compiled the mechanism, all that's left is to write a program for it and check it on the data consisting of n initial lines and m queries. He decided to entrust this job to you.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"190"Polycarp was dismantling his attic and found an old floppy drive on it. A round disc was inserted into the drive with $$$n$$$ integers written on it.Polycarp wrote the numbers from the disk into the $$$a$$$ array. It turned out that the drive works according to the following algorithm:   the drive takes one positive number $$$x$$$ as input and puts a pointer to the first element of the $$$a$$$ array;  after that, the drive starts rotating the disk, every second moving the pointer to the next element, counting the sum of all the elements that have been under the pointer. Since the disk is round, in the $$$a$$$ array, the last element is again followed by the first one;  as soon as the sum is at least $$$x$$$, the drive will shut down. Polycarp wants to learn more about the operation of the drive, but he has absolutely no free time. So he asked you $$$m$$$ questions. To answer the $$$i$$$-th of them, you need to find how many seconds the drive will work if you give it $$$x_i$$$ as input. Please note that in some cases the drive can work infinitely.For example, if $$$n=3, m=3$$$, $$$a=[1, -3, 4]$$$ and $$$x=[1, 5, 2]$$$, then the answers to the questions are as follows:   the answer to the first query is $$$0$$$ because the drive initially points to the first item and the initial sum is $$$1$$$.  the answer to the second query is $$$6$$$, the drive will spin the disk completely twice and the amount becomes $$$1+(-3)+4+1+(-3)+4+1=5$$$.  the answer to the third query is $$$2$$$, the amount is $$$1+(-3)+4=2$$$.  ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"191"You are given $$$n$$$ of integers $$$a_1, a_2, \ldots, a_n$$$. Process $$$q$$$ queries of two types: query of the form ""0 $$$x_j$$$"": add the value $$$x_j$$$ to all even elements of the array $$$a$$$, query of the form ""1 $$$x_j$$$"": add the value $$$x_j$$$ to all odd elements of the array $$$a$$$.Note that when processing the query, we look specifically at the odd/even value of $$$a_i$$$, not its index.After processing each query, print the sum of the elements of the array $$$a$$$.Please note that the answer for some test cases won't fit into 32-bit integer type, so you should use at least 64-bit integer type in your programming language (like long long for C++).",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"192"Let's call a binary string $$$s$$$ awesome, if it has at least $$$1$$$ symbol 1 and length of the string is divisible by the number of 1 in it. In particular, 1, 1010, 111 are awesome, but 0, 110, 01010 aren't.You are given a binary string $$$s$$$. Count the number of its awesome substrings.A string $$$a$$$ is a substring of a string $$$b$$$ if $$$a$$$ can be obtained from $$$b$$$ by deletion of several (possibly, zero or all) characters from the beginning and several (possibly, zero or all) characters from the end.","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"193"You are given one integer $$$n$$$ ($$$n > 1$$$).Recall that a permutation of length $$$n$$$ is an array consisting of $$$n$$$ distinct integers from $$$1$$$ to $$$n$$$ in arbitrary order. For example, $$$[2, 3, 1, 5, 4]$$$ is a permutation of length $$$5$$$, but $$$[1, 2, 2]$$$ is not a permutation ($$$2$$$ appears twice in the array) and $$$[1, 3, 4]$$$ is also not a permutation ($$$n = 3$$$ but there is $$$4$$$ in the array).Your task is to find a permutation $$$p$$$ of length $$$n$$$ that there is no index $$$i$$$ ($$$1 \le i \le n$$$) such that $$$p_i = i$$$ (so, for all $$$i$$$ from $$$1$$$ to $$$n$$$ the condition $$$p_i \ne i$$$ should be satisfied).You have to answer $$$t$$$ independent test cases.If there are several answers, you can print any. It can be proven that the answer exists for each $$$n > 1$$$.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"194"Polycarpus has a sequence, consisting of n non-negative integers: a1, a2, ..., an.Let's define function f(l, r) (l, r are integer, 1 ≤ l ≤ r ≤ n) for sequence a as an operation of bitwise OR of all the sequence elements with indexes from l to r. Formally: f(l, r) = al | al + 1 | ...  | ar. Polycarpus took a piece of paper and wrote out the values of function f(l, r) for all l, r (l, r are integer, 1 ≤ l ≤ r ≤ n). Now he wants to know, how many distinct values he's got in the end. Help Polycarpus, count the number of distinct values of function f(l, r) for the given sequence a.Expression x | y means applying the operation of bitwise OR to numbers x and y. This operation exists in all modern programming languages, for example, in language C++ and Java it is marked as ""|"", in Pascal — as ""or"".",[],"[0, 0, 0, 0, 0, 0, 0, 0]"195"You are given a Young diagram. Given diagram is a histogram with $$$n$$$ columns of lengths $$$a_1, a_2, \ldots, a_n$$$ ($$$a_1 \geq a_2 \geq \ldots \geq a_n \geq 1$$$).    Young diagram for $$$a=[3,2,2,2,1]$$$. Your goal is to find the largest number of non-overlapping dominos that you can draw inside of this histogram, a domino is a $$$1 \times 2$$$ or $$$2 \times 1$$$ rectangle.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"196"Yaroslav thinks that two strings s and w, consisting of digits and having length n are non-comparable if there are two numbers, i and j (1 ≤ i, j ≤ n), such that si > wi and sj < wj. Here sign si represents the i-th digit of string s, similarly, wj represents the j-th digit of string w.A string's template is a string that consists of digits and question marks (""?"").Yaroslav has two string templates, each of them has length n. Yaroslav wants to count the number of ways to replace all question marks by some integers in both templates, so as to make the resulting strings incomparable. Note that the obtained strings can contain leading zeroes and that distinct question marks can be replaced by distinct or the same integers.Help Yaroslav, calculate the remainder after dividing the described number of ways by 1000000007 (109 + 7).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"197"You are given a ternary string (it is a string which consists only of characters '0', '1' and '2').You can swap any two adjacent (consecutive) characters '0' and '1' (i.e. replace ""01"" with ""10"" or vice versa) or any two adjacent (consecutive) characters '1' and '2' (i.e. replace ""12"" with ""21"" or vice versa).For example, for string ""010210"" we can perform the following moves:   ""010210"" $$$\rightarrow$$$ ""100210"";  ""010210"" $$$\rightarrow$$$ ""001210"";  ""010210"" $$$\rightarrow$$$ ""010120"";  ""010210"" $$$\rightarrow$$$ ""010201"". Note than you cannot swap ""02"" $$$\rightarrow$$$ ""20"" and vice versa. You cannot perform any other operations with the given string excluding described above.You task is to obtain the minimum possible (lexicographically) string by using these swaps arbitrary number of times (possibly, zero).String $$$a$$$ is lexicographically less than string $$$b$$$ (if strings $$$a$$$ and $$$b$$$ have the same length) if there exists some position $$$i$$$ ($$$1 \le i \le |a|$$$, where $$$|s|$$$ is the length of the string $$$s$$$) such that for every $$$j < i$$$ holds $$$a_j = b_j$$$, and $$$a_i < b_i$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"198"Due to the coronavirus pandemic, city authorities obligated citizens to keep a social distance. The mayor of the city Semyon wants to light up Gluharniki park so that people could see each other even at night to keep the social distance.The park is a rectangular table with $$$n$$$ rows and $$$m$$$ columns, where the cells of the table are squares, and the boundaries between the cells are streets. External borders are also streets. Every street has length $$$1$$$. For example, park with $$$n=m=2$$$ has $$$12$$$ streets.You were assigned to develop a plan for lighting the park. You can put lanterns in the middle of the streets. The lamp lights two squares near it (or only one square if it stands on the border of the park).    The park sizes are: $$$n=4$$$, $$$m=5$$$. The lighted squares are marked yellow. Please note that all streets have length $$$1$$$. Lanterns are placed in the middle of the streets. In the picture not all the squares are lit. Semyon wants to spend the least possible amount of money on lighting but also wants people throughout the park to keep a social distance. So he asks you to find the minimum number of lanterns that are required to light all the squares.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"199"One day Alice was cleaning up her basement when she noticed something very curious: an infinite set of wooden pieces! Each piece was made of five square tiles, with four tiles adjacent to the fifth center tile:    By the pieces lay a large square wooden board. The board is divided into $$$n^2$$$ cells arranged into $$$n$$$ rows and $$$n$$$ columns. Some of the cells are already occupied by single tiles stuck to it. The remaining cells are free.Alice started wondering whether she could fill the board completely using the pieces she had found. Of course, each piece has to cover exactly five distinct cells of the board, no two pieces can overlap and every piece should fit in the board entirely, without some parts laying outside the board borders. The board however was too large for Alice to do the tiling by hand. Can you help determine if it's possible to fully tile the board?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"200"The marmots need to prepare k problems for HC2 over n days. Each problem, once prepared, also has to be printed.The preparation of a problem on day i (at most one per day) costs ai CHF, and the printing of a problem on day i (also at most one per day) costs bi CHF. Of course, a problem cannot be printed before it has been prepared (but doing both on the same day is fine).What is the minimum cost of preparation and printing?",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"201"Let $$$n$$$ be a positive integer. Let $$$a, b, c$$$ be nonnegative integers such that $$$a + b + c = n$$$.Alice and Bob are gonna play rock-paper-scissors $$$n$$$ times. Alice knows the sequences of hands that Bob will play. However, Alice has to play rock $$$a$$$ times, paper $$$b$$$ times, and scissors $$$c$$$ times.Alice wins if she beats Bob in at least $$$\lceil \frac{n}{2} \rceil$$$ ($$$\frac{n}{2}$$$ rounded up to the nearest integer) hands, otherwise Alice loses.Note that in rock-paper-scissors:  rock beats scissors;  paper beats rock;  scissors beat paper. The task is, given the sequence of hands that Bob will play, and the numbers $$$a, b, c$$$, determine whether or not Alice can win. And if so, find any possible sequence of hands that Alice can use to win.If there are multiple answers, print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"202"There are three sticks with integer lengths $$$l_1, l_2$$$ and $$$l_3$$$.You are asked to break exactly one of them into two pieces in such a way that:   both pieces have positive (strictly greater than $$$0$$$) integer length;  the total length of the pieces is equal to the original length of the stick;  it's possible to construct a rectangle from the resulting four sticks such that each stick is used as exactly one of its sides. A square is also considered a rectangle.Determine if it's possible to do that.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"203"Alice and Bob like games. And now they are ready to start a new game. They have placed n chocolate bars in a line. Alice starts to eat chocolate bars one by one from left to right, and Bob — from right to left. For each chocololate bar the time, needed for the player to consume it, is known (Alice and Bob eat them with equal speed). When the player consumes a chocolate bar, he immediately starts with another. It is not allowed to eat two chocolate bars at the same time, to leave the bar unfinished and to make pauses. If both players start to eat the same bar simultaneously, Bob leaves it to Alice as a true gentleman.How many bars each of the players will consume?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"204"You are given a string s, consisting of lowercase English letters, and the integer m.One should choose some symbols from the given string so that any contiguous subsegment of length m has at least one selected symbol. Note that here we choose positions of symbols, not the symbols themselves.Then one uses the chosen symbols to form a new string. All symbols from the chosen position should be used, but we are allowed to rearrange them in any order.Formally, we choose a subsequence of indices 1 ≤ i1 < i2 < ... < it ≤ |s|. The selected sequence must meet the following condition: for every j such that 1 ≤ j ≤ |s| - m + 1, there must be at least one selected index that belongs to the segment [j,  j + m - 1], i.e. there should exist a k from 1 to t, such that j ≤ ik ≤ j + m - 1.Then we take any permutation p of the selected indices and form a new string sip1sip2... sipt.Find the lexicographically smallest string, that can be obtained using this procedure.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"205"Masha and Grisha like studying sets of positive integers.One day Grisha has written a set A containing n different integers ai on a blackboard. Now he asks Masha to create a set B containing n different integers bj such that all n2 integers that can be obtained by summing up ai and bj for all possible pairs of i and j are different.Both Masha and Grisha don't like big numbers, so all numbers in A are from 1 to 106, and all numbers in B must also be in the same range.Help Masha to create the set B that satisfies Grisha's requirement.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"206"The USA Construction Operation (USACO) recently ordered Farmer John to arrange a row of $$$n$$$ haybale piles on the farm. The $$$i$$$-th pile contains $$$a_i$$$ haybales. However, Farmer John has just left for vacation, leaving Bessie all on her own. Every day, Bessie the naughty cow can choose to move one haybale in any pile to an adjacent pile. Formally, in one day she can choose any two indices $$$i$$$ and $$$j$$$ ($$$1 \le i, j \le n$$$) such that $$$|i-j|=1$$$ and $$$a_i>0$$$ and apply $$$a_i = a_i - 1$$$, $$$a_j = a_j + 1$$$. She may also decide to not do anything on some days because she is lazy.Bessie wants to maximize the number of haybales in pile $$$1$$$ (i.e. to maximize $$$a_1$$$), and she only has $$$d$$$ days to do so before Farmer John returns. Help her find the maximum number of haybales that may be in pile $$$1$$$ if she acts optimally!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"207"There is a frog staying to the left of the string $$$s = s_1 s_2 \ldots s_n$$$ consisting of $$$n$$$ characters (to be more precise, the frog initially stays at the cell $$$0$$$). Each character of $$$s$$$ is either 'L' or 'R'. It means that if the frog is staying at the $$$i$$$-th cell and the $$$i$$$-th character is 'L', the frog can jump only to the left. If the frog is staying at the $$$i$$$-th cell and the $$$i$$$-th character is 'R', the frog can jump only to the right. The frog can jump only to the right from the cell $$$0$$$.Note that the frog can jump into the same cell twice and can perform as many jumps as it needs.The frog wants to reach the $$$n+1$$$-th cell. The frog chooses some positive integer value $$$d$$$ before the first jump (and cannot change it later) and jumps by no more than $$$d$$$ cells at once. I.e. if the $$$i$$$-th character is 'L' then the frog can jump to any cell in a range $$$[max(0, i - d); i - 1]$$$, and if the $$$i$$$-th character is 'R' then the frog can jump to any cell in a range $$$[i + 1; min(n + 1; i + d)]$$$.The frog doesn't want to jump far, so your task is to find the minimum possible value of $$$d$$$ such that the frog can reach the cell $$$n+1$$$ from the cell $$$0$$$ if it can jump by no more than $$$d$$$ cells at once. It is guaranteed that it is always possible to reach $$$n+1$$$ from $$$0$$$.You have to answer $$$t$$$ independent test cases.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"208"Alicia has an array, $$$a_1, a_2, \ldots, a_n$$$, of non-negative integers. For each $$$1 \leq i \leq n$$$, she has found a non-negative integer $$$x_i = max(0, a_1, \ldots, a_{i-1})$$$. Note that for $$$i=1$$$, $$$x_i = 0$$$.For example, if Alicia had the array $$$a = \{0, 1, 2, 0, 3\}$$$, then $$$x = \{0, 0, 1, 2, 2\}$$$.Then, she calculated an array, $$$b_1, b_2, \ldots, b_n$$$: $$$b_i = a_i - x_i$$$.For example, if Alicia had the array $$$a = \{0, 1, 2, 0, 3\}$$$, $$$b = \{0-0, 1-0, 2-1, 0-2, 3-2\} = \{0, 1, 1, -2, 1\}$$$.Alicia gives you the values $$$b_1, b_2, \ldots, b_n$$$ and asks you to restore the values $$$a_1, a_2, \ldots, a_n$$$. Can you help her solve the problem?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"209"Everything is great about Ilya's city, except the roads. The thing is, the only ZooVille road is represented as n holes in a row. We will consider the holes numbered from 1 to n, from left to right.Ilya is really keep on helping his city. So, he wants to fix at least k holes (perharps he can fix more) on a single ZooVille road. The city has m building companies, the i-th company needs ci money units to fix a road segment containing holes with numbers of at least li and at most ri. The companies in ZooVille are very greedy, so, if they fix a segment containing some already fixed holes, they do not decrease the price for fixing the segment. Determine the minimum money Ilya will need to fix at least k holes.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"210"An array $$$b$$$ is called to be a subarray of $$$a$$$ if it forms a continuous subsequence of $$$a$$$, that is, if it is equal to $$$a_l$$$, $$$a_{l + 1}$$$, $$$\ldots$$$, $$$a_r$$$ for some $$$l, r$$$.Suppose $$$m$$$ is some known constant. For any array, having $$$m$$$ or more elements, let's define it's beauty as the sum of $$$m$$$ largest elements of that array. For example:   For array $$$x = [4, 3, 1, 5, 2]$$$ and $$$m = 3$$$, the $$$3$$$ largest elements of $$$x$$$ are $$$5$$$, $$$4$$$ and $$$3$$$, so the beauty of $$$x$$$ is $$$5 + 4 + 3 = 12$$$. For array $$$x = [10, 10, 10]$$$ and $$$m = 2$$$, the beauty of $$$x$$$ is $$$10 + 10 = 20$$$.You are given an array $$$a_1, a_2, \ldots, a_n$$$, the value of the said constant $$$m$$$ and an integer $$$k$$$. Your need to split the array $$$a$$$ into exactly $$$k$$$ subarrays such that:  Each element from $$$a$$$ belongs to exactly one subarray. Each subarray has at least $$$m$$$ elements. The sum of all beauties of $$$k$$$ subarrays is maximum possible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"211"A group of n merry programmers celebrate Robert Floyd's birthday. Polucarpus has got an honourable task of pouring Ber-Cola to everybody. Pouring the same amount of Ber-Cola to everybody is really important. In other words, the drink's volume in each of the n mugs must be the same.Polycarpus has already began the process and he partially emptied the Ber-Cola bottle. Now the first mug has a1 milliliters of the drink, the second one has a2 milliliters and so on. The bottle has b milliliters left and Polycarpus plans to pour them into the mugs so that the main equation was fulfilled.Write a program that would determine what volume of the drink Polycarpus needs to add into each mug to ensure that the following two conditions were fulfilled simultaneously:   there were b milliliters poured in total. That is, the bottle need to be emptied;  after the process is over, the volumes of the drink in the mugs should be equal. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"212"Polycarp has spent the entire day preparing problems for you. Now he has to sleep for at least $$$a$$$ minutes to feel refreshed.Polycarp can only wake up by hearing the sound of his alarm. So he has just fallen asleep and his first alarm goes off in $$$b$$$ minutes.Every time Polycarp wakes up, he decides if he wants to sleep for some more time or not. If he's slept for less than $$$a$$$ minutes in total, then he sets his alarm to go off in $$$c$$$ minutes after it is reset and spends $$$d$$$ minutes to fall asleep again. Otherwise, he gets out of his bed and proceeds with the day.If the alarm goes off while Polycarp is falling asleep, then he resets his alarm to go off in another $$$c$$$ minutes and tries to fall asleep for $$$d$$$ minutes again.You just want to find out when will Polycarp get out of his bed or report that it will never happen.Please check out the notes for some explanations of the example.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"213"The only difference between easy and hard versions is the size of the input.You are given a string $$$s$$$ consisting of $$$n$$$ characters, each character is 'R', 'G' or 'B'.You are also given an integer $$$k$$$. Your task is to change the minimum number of characters in the initial string $$$s$$$ so that after the changes there will be a string of length $$$k$$$ that is a substring of $$$s$$$, and is also a substring of the infinite string ""RGBRGBRGB ..."".A string $$$a$$$ is a substring of string $$$b$$$ if there exists a positive integer $$$i$$$ such that $$$a_1 = b_i$$$, $$$a_2 = b_{i + 1}$$$, $$$a_3 = b_{i + 2}$$$, ..., $$$a_{|a|} = b_{i + |a| - 1}$$$. For example, strings ""GBRG"", ""B"", ""BR"" are substrings of the infinite string ""RGBRGBRGB ..."" while ""GR"", ""RGR"" and ""GGG"" are not.You have to answer $$$q$$$ independent queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"214"Local authorities have heard a lot about combinatorial abilities of Ostap Bender so they decided to ask his help in the question of urbanization. There are n people who plan to move to the cities. The wealth of the i of them is equal to ai. Authorities plan to build two cities, first for n1 people and second for n2 people. Of course, each of n candidates can settle in only one of the cities. Thus, first some subset of candidates of size n1 settle in the first city and then some subset of size n2 is chosen among the remaining candidates and the move to the second city. All other candidates receive an official refuse and go back home.To make the statistic of local region look better in the eyes of their bosses, local authorities decided to pick subsets of candidates in such a way that the sum of arithmetic mean of wealth of people in each of the cities is as large as possible. Arithmetic mean of wealth in one city is the sum of wealth ai among all its residents divided by the number of them (n1 or n2 depending on the city). The division should be done in real numbers without any rounding.Please, help authorities find the optimal way to pick residents for two cities.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"215"After a long party Petya decided to return home, but he turned out to be at the opposite end of the town from his home. There are $$$n$$$ crossroads in the line in the town, and there is either the bus or the tram station at each crossroad.The crossroads are represented as a string $$$s$$$ of length $$$n$$$, where $$$s_i = \texttt{A}$$$, if there is a bus station at $$$i$$$-th crossroad, and $$$s_i = \texttt{B}$$$, if there is a tram station at $$$i$$$-th crossroad. Currently Petya is at the first crossroad (which corresponds to $$$s_1$$$) and his goal is to get to the last crossroad (which corresponds to $$$s_n$$$).If for two crossroads $$$i$$$ and $$$j$$$ for all crossroads $$$i, i+1, \ldots, j-1$$$ there is a bus station, one can pay $$$a$$$ roubles for the bus ticket, and go from $$$i$$$-th crossroad to the $$$j$$$-th crossroad by the bus (it is not necessary to have a bus station at the $$$j$$$-th crossroad). Formally, paying $$$a$$$ roubles Petya can go from $$$i$$$ to $$$j$$$ if $$$s_t = \texttt{A}$$$ for all $$$i \le t < j$$$. If for two crossroads $$$i$$$ and $$$j$$$ for all crossroads $$$i, i+1, \ldots, j-1$$$ there is a tram station, one can pay $$$b$$$ roubles for the tram ticket, and go from $$$i$$$-th crossroad to the $$$j$$$-th crossroad by the tram (it is not necessary to have a tram station at the $$$j$$$-th crossroad). Formally, paying $$$b$$$ roubles Petya can go from $$$i$$$ to $$$j$$$ if $$$s_t = \texttt{B}$$$ for all $$$i \le t < j$$$.For example, if $$$s$$$=""AABBBAB"", $$$a=4$$$ and $$$b=3$$$ then Petya needs:  buy one bus ticket to get from $$$1$$$ to $$$3$$$,  buy one tram ticket to get from $$$3$$$ to $$$6$$$,  buy one bus ticket to get from $$$6$$$ to $$$7$$$. Thus, in total he needs to spend $$$4+3+4=11$$$ roubles. Please note that the type of the stop at the last crossroad (i.e. the character $$$s_n$$$) does not affect the final expense.Now Petya is at the first crossroad, and he wants to get to the $$$n$$$-th crossroad. After the party he has left with $$$p$$$ roubles. He's decided to go to some station on foot, and then go to home using only public transport.Help him to choose the closest crossroad $$$i$$$ to go on foot the first, so he has enough money to get from the $$$i$$$-th crossroad to the $$$n$$$-th, using only tram and bus tickets.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"216"Heidi has finally found the mythical Tree of Life – a legendary combinatorial structure which is said to contain a prophecy crucially needed to defeat the undead armies.On the surface, the Tree of Life is just a regular undirected tree well-known from computer science. This means that it is a collection of n points (called vertices), some of which are connected using n - 1 line segments (edges) so that each pair of vertices is connected by a path (a sequence of one or more edges).To decipher the prophecy, Heidi needs to perform a number of steps. The first is counting the number of lifelines in the tree – these are paths of length 2, i.e., consisting of two edges. Help her!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"217"Ayush is a cashier at the shopping center. Recently his department has started a ''click and collect"" service which allows users to shop online. The store contains k items. n customers have already used the above service. Each user paid for m items. Let aij denote the j-th item in the i-th person's order.Due to the space limitations all the items are arranged in one single row. When Ayush receives the i-th order he will find one by one all the items aij (1 ≤ j ≤ m) in the row. Let pos(x) denote the position of the item x in the row at the moment of its collection. Then Ayush takes time equal to pos(ai1) + pos(ai2) + ... + pos(aim) for the i-th customer.When Ayush accesses the x-th element he keeps a new stock in the front of the row and takes away the x-th element. Thus the values are updating.Your task is to calculate the total time it takes for Ayush to process all the orders.You can assume that the market has endless stock.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"218"A dragon symbolizes wisdom, power and wealth. On Lunar New Year's Day, people model a dragon with bamboo strips and clothes, raise them with rods, and hold the rods high and low to resemble a flying dragon.A performer holding the rod low is represented by a 1, while one holding it high is represented by a 2. Thus, the line of performers can be represented by a sequence a1, a2, ..., an.Little Tommy is among them. He would like to choose an interval [l, r] (1 ≤ l ≤ r ≤ n), then reverse al, al + 1, ..., ar so that the length of the longest non-decreasing subsequence of the new sequence is maximum.A non-decreasing subsequence is a sequence of indices p1, p2, ..., pk, such that p1 < p2 < ... < pk and ap1 ≤ ap2 ≤ ... ≤ apk. The length of the subsequence is k.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"219"The Greatest Secret Ever consists of n words, indexed by positive integers from 1 to n. The secret needs dividing between k Keepers (let's index them by positive integers from 1 to k), the i-th Keeper gets a non-empty set of words with numbers from the set Ui = (ui, 1, ui, 2, ..., ui, |Ui|). Here and below we'll presuppose that the set elements are written in the increasing order.We'll say that the secret is safe if the following conditions are hold:  for any two indexes i, j (1 ≤ i < j ≤ k) the intersection of sets Ui and Uj is an empty set;  the union of sets U1, U2, ..., Uk is set (1, 2, ..., n);  in each set Ui, its elements ui, 1, ui, 2, ..., ui, |Ui| do not form an arithmetic progression (in particular, |Ui| ≥ 3 should hold). Let us remind you that the elements of set (u1, u2, ..., us) form an arithmetic progression if there is such number d, that for all i (1 ≤ i < s) fulfills ui + d = ui + 1. For example, the elements of sets (5), (1, 10) and (1, 5, 9) form arithmetic progressions and the elements of sets (1, 2, 4) and (3, 6, 8) don't.Your task is to find any partition of the set of words into subsets U1, U2, ..., Uk so that the secret is safe. Otherwise indicate that there's no such partition.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"220"Vasya writes his own library for building graphical user interface. Vasya called his creation VTK (VasyaToolKit). One of the interesting aspects of this library is that widgets are packed in each other. A widget is some element of graphical interface. Each widget has width and height, and occupies some rectangle on the screen. Any widget in Vasya's library is of type Widget. For simplicity we will identify the widget and its type. Types HBox and VBox are derivatives of type Widget, so they also are types Widget. Widgets HBox and VBox are special. They can store other widgets. Both those widgets can use the pack() method to pack directly in itself some other widget. Widgets of types HBox and VBox can store several other widgets, even several equal widgets — they will simply appear several times. As a result of using the method pack() only the link to the packed widget is saved, that is when the packed widget is changed, its image in the widget, into which it is packed, will also change. We shall assume that the widget a is packed in the widget b if there exists a chain of widgets a = c1, c2, ..., ck = b, k ≥ 2, for which ci is packed directly to ci + 1 for any 1 ≤ i < k. In Vasya's library the situation when the widget a is packed in the widget a (that is, in itself) is not allowed. If you try to pack the widgets into each other in this manner immediately results in an error.Also, the widgets HBox and VBox have parameters border and spacing, which are determined by the methods set_border() and set_spacing() respectively. By default both of these options equal 0.    The picture above shows how the widgets are packed into HBox and VBox. At that HBox and VBox automatically change their size depending on the size of packed widgets. As for HBox and VBox, they only differ in that in HBox the widgets are packed horizontally and in VBox — vertically. The parameter spacing sets the distance between adjacent widgets, and border — a frame around all packed widgets of the desired width. Packed widgets are placed exactly in the order in which the pack() method was called for them. If within HBox or VBox there are no packed widgets, their sizes are equal to 0 × 0, regardless of the options border and spacing. The construction of all the widgets is performed using a scripting language VasyaScript. The description of the language can be found in the input data. For the final verification of the code Vasya asks you to write a program that calculates the sizes of all the widgets on the source code in the language of VasyaScript. ",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"221"You are given two integers $$$b$$$ and $$$w$$$. You have a chessboard of size $$$10^9 \times 10^9$$$ with the top left cell at $$$(1; 1)$$$, the cell $$$(1; 1)$$$ is painted white.Your task is to find a connected component on this chessboard that contains exactly $$$b$$$ black cells and exactly $$$w$$$ white cells. Two cells are called connected if they share a side (i.e. for the cell $$$(x, y)$$$ there are at most four connected cells: $$$(x - 1, y), (x + 1, y), (x, y - 1), (x, y + 1)$$$). A set of cells is called a connected component if for every pair of cells $$$C_1$$$ and $$$C_2$$$ from this set, there exists a sequence of cells $$$c_1$$$, $$$c_2$$$, ..., $$$c_k$$$ such that $$$c_1 = C_1$$$, $$$c_k = C_2$$$, all $$$c_i$$$ from $$$1$$$ to $$$k$$$ are belong to this set of cells and for every $$$i \in [1, k - 1]$$$, cells $$$c_i$$$ and $$$c_{i + 1}$$$ are connected.Obviously, it can be impossible to find such component. In this case print ""NO"". Otherwise, print ""YES"" and any suitable connected component.You have to answer $$$q$$$ independent queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"222"You have array a that contains all integers from 1 to n twice. You can arbitrary permute any numbers in a.Let number i be in positions xi, yi (xi < yi) in the permuted array a. Let's define the value di = yi - xi — the distance between the positions of the number i. Permute the numbers in array a to minimize the value of the sum .",[],"[0, 0, 0, 0, 0, 0, 0, 0]"223"For the New Year, Polycarp decided to send postcards to all his $$$n$$$ friends. He wants to make postcards with his own hands. For this purpose, he has a sheet of paper of size $$$w \times h$$$, which can be cut into pieces.Polycarp can cut any sheet of paper $$$w \times h$$$ that he has in only two cases:   If $$$w$$$ is even, then he can cut the sheet in half and get two sheets of size $$$\frac{w}{2} \times h$$$;  If $$$h$$$ is even, then he can cut the sheet in half and get two sheets of size $$$w \times \frac{h}{2}$$$; If $$$w$$$ and $$$h$$$ are even at the same time, then Polycarp can cut the sheet according to any of the rules above.After cutting a sheet of paper, the total number of sheets of paper is increased by $$$1$$$.Help Polycarp to find out if he can cut his sheet of size $$$w \times h$$$ at into $$$n$$$ or more pieces, using only the rules described above.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"224"You like the card board game ""Set"". Each card contains $$$k$$$ features, each of which is equal to a value from the set $$$\{0, 1, 2\}$$$. The deck contains all possible variants of cards, that is, there are $$$3^k$$$ different cards in total.A feature for three cards is called good if it is the same for these cards or pairwise distinct. Three cards are called a set if all $$$k$$$ features are good for them.For example, the cards $$$(0, 0, 0)$$$, $$$(0, 2, 1)$$$, and $$$(0, 1, 2)$$$ form a set, but the cards $$$(0, 2, 2)$$$, $$$(2, 1, 2)$$$, and $$$(1, 2, 0)$$$ do not, as, for example, the last feature is not good.A group of five cards is called a meta-set, if there is strictly more than one set among them. How many meta-sets there are among given $$$n$$$ distinct cards?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"225"Let's consider the famous game called Boom (aka Hat) with simplified rules.There are n teams playing the game. Each team has two players. The purpose of the game is to explain the words to the teammate without using any words that contain the same root or that sound similarly. Player j from team i (1 ≤ i ≤ n, 1 ≤ j ≤ 2) is characterized by two numbers: aij and bij. The numbers correspondingly represent the skill of explaining and the skill of understanding this particular player has. Besides, m cards are used for the game. Each card has a word written on it. The card number k (1 ≤ k ≤ m) is characterized by number ck — the complexity of the word it contains.Before the game starts the cards are put in a deck and shuffled. Then the teams play in turns like that: the 1-st player of the 1-st team, the 1-st player of the 2-nd team, ... , the 1-st player of the n-th team, the 2-nd player of the 1-st team, ... , the 2-nd player of the n-th team, the 1-st player of the 1-st team and so on.Each turn continues for t seconds. It goes like that: Initially the time for each turn is t. While the time left to a player is more than 0, a player takes a card from the top of the deck and starts explaining the word it has to his teammate. The time needed for the j-th player of the i-th team to explain the word from the card k to his teammate (the q-th player of the i-th team) equals max(1, ck - (aij + biq) - dik) (if j = 1,  then q = 2,  else q = 1). The value dik is the number of seconds the i-th team has already spent explaining the word k during the previous turns. Initially, all dik equal 0. If a team manages to guess the word before the end of the turn, then the time given above is substracted from the duration of the turn, the card containing the guessed word leaves the game, the team wins one point and the game continues. If the team doesn't manage to guess the word, then the card is put at the bottom of the deck, dik increases on the amount of time of the turn, spent on explaining the word. Thus, when this team gets the very same word, they start explaining it not from the beginning, but from the point where they stopped. The game ends when words from all m cards are guessed correctly.You are given n teams and a deck of m cards. You should determine for each team, how many points it will have by the end of the game and which words the team will have guessed.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"226"Om Nom really likes candies and doesn't like spiders as they frequently steal candies. One day Om Nom fancied a walk in a park. Unfortunately, the park has some spiders and Om Nom doesn't want to see them at all.  The park can be represented as a rectangular n × m field. The park has k spiders, each spider at time 0 is at some cell of the field. The spiders move all the time, and each spider always moves in one of the four directions (left, right, down, up). In a unit of time, a spider crawls from his cell to the side-adjacent cell in the corresponding direction. If there is no cell in the given direction, then the spider leaves the park. The spiders do not interfere with each other as they move. Specifically, one cell can have multiple spiders at the same time.Om Nom isn't yet sure where to start his walk from but he definitely wants:  to start walking at time 0 at an upper row cell of the field (it is guaranteed that the cells in this row do not contain any spiders);  to walk by moving down the field towards the lowest row (the walk ends when Om Nom leaves the boundaries of the park). We know that Om Nom moves by jumping. One jump takes one time unit and transports the little monster from his cell to either a side-adjacent cell on the lower row or outside the park boundaries.Each time Om Nom lands in a cell he sees all the spiders that have come to that cell at this moment of time. Om Nom wants to choose the optimal cell to start the walk from. That's why he wonders: for each possible starting cell, how many spiders will he see during the walk if he starts from this cell? Help him and calculate the required value for each possible starting cell.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"227"Simon has an array a1, a2, ..., an, consisting of n positive integers. Today Simon asked you to find a pair of integers l, r (1 ≤ l ≤ r ≤ n), such that the following conditions hold:  there is integer j (l ≤ j ≤ r), such that all integers al, al + 1, ..., ar are divisible by aj;  value r - l takes the maximum value among all pairs for which condition 1 is true; Help Simon, find the required pair of numbers (l, r). If there are multiple required pairs find all of them.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"228"This is an interactive problem.Kochiya Sanae is playing with magnets. Realizing that some of those magnets are demagnetized, she is curious to find them out.There are $$$n$$$ magnets, which can be of the following $$$3$$$ types: N  S  - — these magnets are demagnetized. Note that you don't know the types of these magnets beforehand.You have a machine which can measure the force between the magnets, and you can use it at most $$$n+\lfloor \log_2n\rfloor$$$ times.You can put some magnets to the left part of the machine and some to the right part of the machine, and launch the machine. Obviously, you can put one magnet to at most one side (you don't have to put all magnets). You can put the same magnet in different queries.Then the machine will tell the force these magnets produce. Formally, let $$$n_1,s_1$$$ be the number of N and S magnets correspondently on the left and $$$n_2,s_2$$$ — on the right. Then the force between them would be $$$n_1n_2+s_1s_2-n_1s_2-n_2s_1$$$. Please note that the force is a signed value.However, when the absolute value of the force is strictly larger than $$$n$$$, the machine will crash into pieces.You need to find all magnets of type - (all demagnetized ones), without breaking the machine.Note that the interactor is not adaptive. The types of the magnets are fixed before the start of the interaction and do not change with queries.It is guaranteed that there are at least $$$2$$$ magnets whose type is not -, and at least $$$1$$$ magnet of type -.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"229"We call a string good, if after merging all the consecutive equal characters, the resulting string is palindrome. For example, ""aabba"" is good, because after the merging step it will become ""aba"".Given a string, you have to find two values:  the number of good substrings of even length;  the number of good substrings of odd length. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"230"YouKn0wWho has an integer sequence $$$a_1, a_2, \ldots a_n$$$. Now he will split the sequence $$$a$$$ into one or more consecutive subarrays so that each element of $$$a$$$ belongs to exactly one subarray. Let $$$k$$$ be the number of resulting subarrays, and $$$h_1, h_2, \ldots, h_k$$$ be the lengths of the longest increasing subsequences of corresponding subarrays.For example, if we split $$$[2, 5, 3, 1, 4, 3, 2, 2, 5, 1]$$$ into $$$[2, 5, 3, 1, 4]$$$, $$$[3, 2, 2, 5]$$$, $$$[1]$$$, then $$$h = [3, 2, 1]$$$.YouKn0wWho wonders if it is possible to split the sequence $$$a$$$ in such a way that the bitwise XOR of $$$h_1, h_2, \ldots, h_k$$$ is equal to $$$0$$$. You have to tell whether it is possible.The longest increasing subsequence (LIS) of a sequence $$$b_1, b_2, \ldots, b_m$$$ is the longest sequence of valid indices $$$i_1, i_2, \ldots, i_k$$$ such that $$$i_1 \lt i_2 \lt \ldots \lt i_k$$$ and $$$b_{i_1} \lt b_{i_2} \lt \ldots \lt b_{i_k}$$$. For example, the LIS of $$$[2, 5, 3, 3, 5]$$$ is $$$[2, 3, 5]$$$, which has length $$$3$$$.An array $$$c$$$ is a subarray of an array $$$b$$$ if $$$c$$$ can be obtained from $$$b$$$ by deletion of several (possibly, zero or all) elements from the beginning and several (possibly, zero or all) elements from the end.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"231"In the Bus of Characters there are $$$n$$$ rows of seat, each having $$$2$$$ seats. The width of both seats in the $$$i$$$-th row is $$$w_i$$$ centimeters. All integers $$$w_i$$$ are distinct.Initially the bus is empty. On each of $$$2n$$$ stops one passenger enters the bus. There are two types of passengers:   an introvert always chooses a row where both seats are empty. Among these rows he chooses the one with the smallest seats width and takes one of the seats in it;  an extrovert always chooses a row where exactly one seat is occupied (by an introvert). Among these rows he chooses the one with the largest seats width and takes the vacant place in it. You are given the seats width in each row and the order the passengers enter the bus. Determine which row each passenger will take.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"232"To confuse the opponents, the Galactic Empire represents fractions in an unusual format. The fractions are represented as two sets of integers. The product of numbers from the first set gives the fraction numerator, the product of numbers from the second set gives the fraction denominator. However, it turned out that the programs that work with fractions in this representations aren't complete, they lack supporting the operation of reducing fractions. Implement this operation and the Empire won't forget you.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"233"A sequence of $$$n$$$ non-negative integers ($$$n \ge 2$$$) $$$a_1, a_2, \dots, a_n$$$ is called good if for all $$$i$$$ from $$$1$$$ to $$$n-1$$$ the following condition holds true: $$$$$$a_1 \: \& \: a_2 \: \& \: \dots \: \& \: a_i = a_{i+1} \: \& \: a_{i+2} \: \& \: \dots \: \& \: a_n,$$$$$$ where $$$\&$$$ denotes the bitwise AND operation.You are given an array $$$a$$$ of size $$$n$$$ ($$$n \geq 2$$$). Find the number of permutations $$$p$$$ of numbers ranging from $$$1$$$ to $$$n$$$, for which the sequence $$$a_{p_1}$$$, $$$a_{p_2}$$$, ... ,$$$a_{p_n}$$$ is good. Since this number can be large, output it modulo $$$10^9+7$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"234"This is the hard version of the problem. The only difference is the constraints on $$$n$$$ and $$$k$$$. You can make hacks only if all versions of the problem are solved.You have a string $$$s$$$, and you can do two types of operations on it:   Delete the last character of the string.  Duplicate the string: $$$s:=s+s$$$, where $$$+$$$ denotes concatenation. You can use each operation any number of times (possibly none).Your task is to find the lexicographically smallest string of length exactly $$$k$$$ that can be obtained by doing these operations on string $$$s$$$.A string $$$a$$$ is lexicographically smaller than a string $$$b$$$ if and only if one of the following holds:  $$$a$$$ is a prefix of $$$b$$$, but $$$a\ne b$$$;  In the first position where $$$a$$$ and $$$b$$$ differ, the string $$$a$$$ has a letter that appears earlier in the alphabet than the corresponding letter in $$$b$$$. ",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"235"Vasya is currently at a car rental service, and he wants to reach cinema. The film he has bought a ticket for starts in t minutes. There is a straight road of length s from the service to the cinema. Let's introduce a coordinate system so that the car rental service is at the point 0, and the cinema is at the point s.There are k gas stations along the road, and at each of them you can fill a car with any amount of fuel for free! Consider that this operation doesn't take any time, i.e. is carried out instantly.There are n cars in the rental service, i-th of them is characterized with two integers ci and vi — the price of this car rent and the capacity of its fuel tank in liters. It's not allowed to fuel a car with more fuel than its tank capacity vi. All cars are completely fueled at the car rental service.Each of the cars can be driven in one of two speed modes: normal or accelerated. In the normal mode a car covers 1 kilometer in 2 minutes, and consumes 1 liter of fuel. In the accelerated mode a car covers 1 kilometer in 1 minutes, but consumes 2 liters of fuel. The driving mode can be changed at any moment and any number of times.Your task is to choose a car with minimum price such that Vasya can reach the cinema before the show starts, i.e. not later than in t minutes. Assume that all cars are completely fueled initially.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"236"You have an array a consisting of n integers. Each integer from 1 to n appears exactly once in this array.For some indices i (1 ≤ i ≤ n - 1) it is possible to swap i-th element with (i + 1)-th, for other indices it is not possible. You may perform any number of swapping operations any order. There is no limit on the number of times you swap i-th element with (i + 1)-th (if the position is not forbidden).Can you make this array sorted in ascending order performing some sequence of swapping operations?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"237"Qpwoeirut has taken up architecture and ambitiously decided to remodel his city.Qpwoeirut's city can be described as a row of $$$n$$$ buildings, the $$$i$$$-th ($$$1 \le i \le n$$$) of which is $$$h_i$$$ floors high. You can assume that the height of every floor in this problem is equal. Therefore, building $$$i$$$ is taller than the building $$$j$$$ if and only if the number of floors $$$h_i$$$ in building $$$i$$$ is larger than the number of floors $$$h_j$$$ in building $$$j$$$.Building $$$i$$$ is cool if it is taller than both building $$$i-1$$$ and building $$$i+1$$$ (and both of them exist). Note that neither the $$$1$$$-st nor the $$$n$$$-th building can be cool.To remodel the city, Qpwoeirut needs to maximize the number of cool buildings. To do this, Qpwoeirut can build additional floors on top of any of the buildings to make them taller. Note that he cannot remove already existing floors.Since building new floors is expensive, Qpwoeirut wants to minimize the number of floors he builds. Find the minimum number of floors Qpwoeirut needs to build in order to maximize the number of cool buildings.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"238"The only difference between the easy and hard versions is that the given string $$$s$$$ in the easy version is initially a palindrome, this condition is not always true for the hard version.A palindrome is a string that reads the same left to right and right to left. For example, ""101101"" is a palindrome, while ""0101"" is not.Alice and Bob are playing a game on a string $$$s$$$ (which is initially a palindrome in this version) of length $$$n$$$ consisting of the characters '0' and '1'. Both players take alternate turns with Alice going first.In each turn, the player can perform one of the following operations:   Choose any $$$i$$$ ($$$1 \le i \le n$$$), where $$$s[i] =$$$ '0' and change $$$s[i]$$$ to '1'. Pay 1 dollar.  Reverse the whole string, pay 0 dollars. This operation is only allowed if the string is currently not a palindrome, and the last operation was not reverse. That is, if Alice reverses the string, then Bob can't reverse in the next move, and vice versa. Reversing a string means reordering its letters from the last to the first. For example, ""01001"" becomes ""10010"" after reversing.The game ends when every character of string becomes '1'. The player who spends minimum dollars till this point wins the game and it is a draw if both spend equal dollars. If both players play optimally, output whether Alice wins, Bob wins, or if it is a draw.",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"239"In this problem, we will deal with binary strings. Each character of a binary string is either a 0 or a 1. We will also deal with substrings; recall that a substring is a contiguous subsequence of a string. We denote the substring of string $$$s$$$ starting from the $$$l$$$-th character and ending with the $$$r$$$-th character as $$$s[l \dots r]$$$. The characters of each string are numbered from $$$1$$$.We can perform several operations on the strings we consider. Each operation is to choose a substring of our string and replace it with another string. There are two possible types of operations: replace 011 with 110, or replace 110 with 011. For example, if we apply exactly one operation to the string 110011110, it can be transformed into 011011110, 110110110, or 110011011.Binary string $$$a$$$ is considered reachable from binary string $$$b$$$ if there exists a sequence $$$s_1$$$, $$$s_2$$$, ..., $$$s_k$$$ such that $$$s_1 = a$$$, $$$s_k = b$$$, and for every $$$i \in [1, k - 1]$$$, $$$s_i$$$ can be transformed into $$$s_{i + 1}$$$ using exactly one operation. Note that $$$k$$$ can be equal to $$$1$$$, i. e., every string is reachable from itself.You are given a string $$$t$$$ and $$$q$$$ queries to it. Each query consists of three integers $$$l_1$$$, $$$l_2$$$ and $$$len$$$. To answer each query, you have to determine whether $$$t[l_1 \dots l_1 + len - 1]$$$ is reachable from $$$t[l_2 \dots l_2 + len - 1]$$$.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"240"Let's call an array good if there is an element in the array that equals to the sum of all other elements. For example, the array $$$a=[1, 3, 3, 7]$$$ is good because there is the element $$$a_4=7$$$ which equals to the sum $$$1 + 3 + 3$$$.You are given an array $$$a$$$ consisting of $$$n$$$ integers. Your task is to print all indices $$$j$$$ of this array such that after removing the $$$j$$$-th element from the array it will be good (let's call such indices nice).For example, if $$$a=[8, 3, 5, 2]$$$, the nice indices are $$$1$$$ and $$$4$$$:   if you remove $$$a_1$$$, the array will look like $$$[3, 5, 2]$$$ and it is good;  if you remove $$$a_4$$$, the array will look like $$$[8, 3, 5]$$$ and it is good. You have to consider all removals independently, i. e. remove the element, check if the resulting array is good, and return the element into the array.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"241There are n lights aligned in a row. These lights are numbered 1 to n from left to right. Initially some of the lights are switched on. Shaass wants to switch all the lights on. At each step he can switch a light on (this light should be switched off at that moment) if there's at least one adjacent light which is already switched on. He knows the initial state of lights and he's wondering how many different ways there exist to switch all the lights on. Please find the required number of ways modulo 1000000007 (109 + 7).,['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"242"Once upon a time in the Kingdom of Far Far Away lived Sam the Farmer. Sam had a cow named Dawn and he was deeply attached to her. Sam would spend the whole summer stocking hay to feed Dawn in winter. Sam scythed hay and put it into haystack. As Sam was a bright farmer, he tried to make the process of storing hay simpler and more convenient to use. He collected the hay into cubical hay blocks of the same size. Then he stored the blocks in his barn. After a summer spent in hard toil Sam stored A·B·C hay blocks and stored them in a barn as a rectangular parallelepiped A layers high. Each layer had B rows and each row had C blocks.At the end of the autumn Sam came into the barn to admire one more time the hay he'd been stacking during this hard summer. Unfortunately, Sam was horrified to see that the hay blocks had been carelessly scattered around the barn. The place was a complete mess. As it turned out, thieves had sneaked into the barn. They completely dissembled and took away a layer of blocks from the parallelepiped's front, back, top and sides. As a result, the barn only had a parallelepiped containing (A - 1) × (B - 2) × (C - 2) hay blocks. To hide the evidence of the crime, the thieves had dissembled the parallelepiped into single 1 × 1 × 1 blocks and scattered them around the barn. After the theft Sam counted n hay blocks in the barn but he forgot numbers A, B и C.Given number n, find the minimally possible and maximally possible number of stolen hay blocks.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"243"Note that the only difference between the easy and hard version is the constraint on the number of queries. You can make hacks only if all versions of the problem are solved.This is an interactive problem.You are given a tree consisting of $$$n$$$ nodes numbered with integers from $$$1$$$ to $$$n$$$. Ayush and Ashish chose two secret distinct nodes in the tree. You need to find out both the nodes. You can make the following query:   Provide a list of nodes and you will receive a node from that list whose sum of distances to both the hidden nodes is minimal (if there are multiple such nodes in the list, you will receive any one of them). You will also get the sum of distances of that node to the hidden nodes. Recall that a tree is a connected graph without cycles. The distance between two nodes is defined as the number of edges in the simple path between them.More formally, let's define two hidden nodes as $$$s$$$ and $$$f$$$. In one query you can provide the set of nodes $$$\{a_1, a_2, \ldots, a_c\}$$$ of the tree. As a result, you will get two numbers $$$a_i$$$ and $$$dist(a_i, s) + dist(a_i, f)$$$. The node $$$a_i$$$ is any node from the provided set, for which the number $$$dist(a_i, s) + dist(a_i, f)$$$ is minimal.You can ask no more than $$$11$$$ queries.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"244"Notice that the memory limit is non-standard.Recently Arthur and Sasha have studied correct bracket sequences. Arthur understood this topic perfectly and become so amazed about correct bracket sequences, so he even got himself a favorite correct bracket sequence of length 2n. Unlike Arthur, Sasha understood the topic very badly, and broke Arthur's favorite correct bracket sequence just to spite him.All Arthur remembers about his favorite sequence is for each opening parenthesis ('(') the approximate distance to the corresponding closing one (')'). For the i-th opening bracket he remembers the segment [li, ri], containing the distance to the corresponding closing bracket.Formally speaking, for the i-th opening bracket (in order from left to right) we know that the difference of its position and the position of the corresponding closing bracket belongs to the segment [li, ri].Help Arthur restore his favorite correct bracket sequence!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"245"Petya has an array of integers $$$a_1, a_2, \ldots, a_n$$$. He only likes sorted arrays. Unfortunately, the given array could be arbitrary, so Petya wants to sort it.Petya likes to challenge himself, so he wants to sort array using only $$$3$$$-cycles. More formally, in one operation he can pick $$$3$$$ pairwise distinct indices $$$i$$$, $$$j$$$, and $$$k$$$ ($$$1 \leq i, j, k \leq n$$$) and apply $$$i \to j \to k \to i$$$ cycle to the array $$$a$$$. It simultaneously places $$$a_i$$$ on position $$$j$$$, $$$a_j$$$ on position $$$k$$$, and $$$a_k$$$ on position $$$i$$$, without changing any other element.For example, if $$$a$$$ is $$$[10, 50, 20, 30, 40, 60]$$$ and he chooses $$$i = 2$$$, $$$j = 1$$$, $$$k = 5$$$, then the array becomes $$$[\underline{50}, \underline{40}, 20, 30, \underline{10}, 60]$$$.Petya can apply arbitrary number of $$$3$$$-cycles (possibly, zero). You are to determine if Petya can sort his array $$$a$$$, i. e. make it non-decreasing.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"246"Recently in school Alina has learned what are the persistent data structures: they are data structures that always preserves the previous version of itself and access to it when it is modified.After reaching home Alina decided to invent her own persistent data structure. Inventing didn't take long: there is a bookcase right behind her bed. Alina thinks that the bookcase is a good choice for a persistent data structure. Initially the bookcase is empty, thus there is no book at any position at any shelf.The bookcase consists of n shelves, and each shelf has exactly m positions for books at it. Alina enumerates shelves by integers from 1 to n and positions at shelves — from 1 to m. Initially the bookcase is empty, thus there is no book at any position at any shelf in it.Alina wrote down q operations, which will be consecutively applied to the bookcase. Each of the operations has one of four types: 1 i j — Place a book at position j at shelf i if there is no book at it. 2 i j — Remove the book from position j at shelf i if there is a book at it. 3 i — Invert book placing at shelf i. This means that from every position at shelf i which has a book at it, the book should be removed, and at every position at shelf i which has not book at it, a book should be placed. 4 k — Return the books in the bookcase in a state they were after applying k-th operation. In particular, k = 0 means that the bookcase should be in initial state, thus every book in the bookcase should be removed from its position.After applying each of operation Alina is interested in the number of books in the bookcase. Alina got 'A' in the school and had no problem finding this values. Will you do so?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"247"One day Vasya was on a physics practical, performing the task on measuring the capacitance. He followed the teacher's advice and did as much as n measurements, and recorded the results in the notebook. After that he was about to show the results to the teacher, but he remembered that at the last lesson, the teacher had made his friend Petya redo the experiment because the largest and the smallest results differed by more than two times. Vasya is lazy, and he does not want to redo the experiment. He wants to do the task and go home play computer games. So he decided to cheat: before Vasya shows the measurements to the teacher, he will erase some of them, so as to make the largest and the smallest results of the remaining measurements differ in no more than two times. In other words, if the remaining measurements have the smallest result x, and the largest result y, then the inequality y ≤ 2·x must fulfill. Of course, to avoid the teacher's suspicion, Vasya wants to remove as few measurement results as possible from his notes.Help Vasya, find what minimum number of measurement results he will have to erase from his notes so that the largest and the smallest of the remaining results of the measurements differed in no more than two times.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"248"Polycarp has $$$n$$$ friends, the $$$i$$$-th of his friends has $$$a_i$$$ candies. Polycarp's friends do not like when they have different numbers of candies. In other words they want all $$$a_i$$$ to be the same. To solve this, Polycarp performs the following set of actions exactly once:   Polycarp chooses $$$k$$$ ($$$0 \le k \le n$$$) arbitrary friends (let's say he chooses friends with indices $$$i_1, i_2, \ldots, i_k$$$);  Polycarp distributes their $$$a_{i_1} + a_{i_2} + \ldots + a_{i_k}$$$ candies among all $$$n$$$ friends. During distribution for each of $$$a_{i_1} + a_{i_2} + \ldots + a_{i_k}$$$ candies he chooses new owner. That can be any of $$$n$$$ friends. Note, that any candy can be given to the person, who has owned that candy before the distribution process. Note that the number $$$k$$$ is not fixed in advance and can be arbitrary. Your task is to find the minimum value of $$$k$$$.For example, if $$$n=4$$$ and $$$a=[4, 5, 2, 5]$$$, then Polycarp could make the following distribution of the candies:   Polycarp chooses $$$k=2$$$ friends with indices $$$i=[2, 4]$$$ and distributes $$$a_2 + a_4 = 10$$$ candies to make $$$a=[4, 4, 4, 4]$$$ (two candies go to person $$$3$$$). Note that in this example Polycarp cannot choose $$$k=1$$$ friend so that he can redistribute candies so that in the end all $$$a_i$$$ are equal.For the data $$$n$$$ and $$$a$$$, determine the minimum value $$$k$$$. With this value $$$k$$$, Polycarp should be able to select $$$k$$$ friends and redistribute their candies so that everyone will end up with the same number of candies.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"249"String s of length n is called k-palindrome, if it is a palindrome itself, and its prefix and suffix of length  are (k - 1)-palindromes. By definition, any string (even empty) is 0-palindrome.Let's call the palindrome degree of string s such a maximum number k, for which s is k-palindrome. For example, ""abaaba"" has degree equals to 3.You are given a string. Your task is to find the sum of the palindrome degrees of all its prefixes.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"250"The employees of the F company have lots of ways to entertain themselves. Today they invited a famous magician who shows a trick with plastic cups and a marble.The point is to trick the spectator's attention. Initially, the spectator stands in front of a line of n plastic cups. Then the magician places a small marble under one cup and shuffles the cups. Then the spectator should guess which cup hides the marble.But the head coder of the F company isn't easy to trick. When he saw the performance, he noticed several important facts:  each cup contains a mark — a number from 1 to n; all marks on the cups are distinct;  the magician shuffles the cups in m operations, each operation looks like that: take a cup marked xi, sitting at position yi in the row of cups (the positions are numbered from left to right, starting from 1) and shift it to the very beginning of the cup row (on the first position). When the head coder came home after work he wanted to re-do the trick. Unfortunately, he didn't remember the starting or the final position of the cups. He only remembered which operations the magician performed. Help the coder: given the operations in the order they were made find at least one initial permutation of the cups that can go through the described operations in the given order. Otherwise, state that such permutation doesn't exist.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"251"Valera conducts experiments with algorithms that search for shortest paths. He has recently studied the Floyd's algorithm, so it's time to work with it.Valera's already written the code that counts the shortest distance between any pair of vertexes in a non-directed connected graph from n vertexes and m edges, containing no loops and multiple edges. Besides, Valera's decided to mark part of the vertexes. He's marked exactly k vertexes a1, a2, ..., ak.Valera's code is given below.ans[i][j] // the shortest distance for a pair of vertexes i, ja[i]  // vertexes, marked by Valerafor(i = 1; i <= n; i++) {    for(j = 1; j <= n; j++) {        if (i == j)            ans[i][j] = 0;        else            ans[i][j] = INF;  //INF is a very large number     }}    for(i = 1; i <= m; i++) {    read a pair of vertexes u, v that have a non-directed edge between them;    ans[u][v] = 1;    ans[v][u] = 1;}for (i = 1; i <= k; i++) {    v = a[i];    for(j = 1; j <= n; j++)        for(r = 1; r <= n; r++)            ans[j][r] = min(ans[j][r], ans[j][v] + ans[v][r]);}Valera has seen that his code is wrong. Help the boy. Given the set of marked vertexes a1, a2, ..., ak, find such non-directed connected graph, consisting of n vertexes and m edges, for which Valera's code counts the wrong shortest distance for at least one pair of vertexes (i, j). Valera is really keen to get a graph without any loops and multiple edges. If no such graph exists, print -1.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"252"This is a hard version of the problem. The actual problems are different, but the easy version is almost a subtask of the hard version. Note that the constraints and the output format are different.You are given a string $$$s$$$ consisting of $$$n$$$ lowercase Latin letters.You have to color all its characters the minimum number of colors (each character to exactly one color, the same letters can be colored the same or different colors, i.e. you can choose exactly one color for each index in $$$s$$$).After coloring, you can swap any two neighboring characters of the string that are colored different colors. You can perform such an operation arbitrary (possibly, zero) number of times.The goal is to make the string sorted, i.e. all characters should be in alphabetical order.Your task is to find the minimum number of colors which you have to color the given string in so that after coloring it can become sorted by some sequence of swaps. Note that you have to restore only coloring, not the sequence of swaps.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"253"Alice and Bob have received three big piles of candies as a gift. Now they want to divide these candies as fair as possible. To do this, Alice takes one pile of candies, then Bob takes one of the other two piles. The last pile is split between Alice and Bob as they want: for example, it is possible that Alice takes the whole pile, and Bob gets nothing from it.After taking the candies from the piles, if Alice has more candies than Bob, she discards some candies so that the number of candies she has is equal to the number of candies Bob has. Of course, Bob does the same if he has more candies.Alice and Bob want to have as many candies as possible, and they plan the process of dividing candies accordingly. Please calculate the maximum number of candies Alice can have after this division process (of course, Bob will have the same number of candies).You have to answer $$$q$$$ independent queries.Let's see the following example: $$$[1, 3, 4]$$$. Then Alice can choose the third pile, Bob can take the second pile, and then the only candy from the first pile goes to Bob — then Alice has $$$4$$$ candies, and Bob has $$$4$$$ candies.Another example is $$$[1, 10, 100]$$$. Then Alice can choose the second pile, Bob can choose the first pile, and candies from the third pile can be divided in such a way that Bob takes $$$54$$$ candies, and Alice takes $$$46$$$ candies. Now Bob has $$$55$$$ candies, and Alice has $$$56$$$ candies, so she has to discard one candy — and after that, she has $$$55$$$ candies too.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"254"This is the second subtask of problem F. The only differences between this and the first subtask are the constraints on the value of $$$m$$$ and the time limit. It is sufficient to solve this subtask in order to hack it, but you need to solve both subtasks in order to hack the first one.There are $$$n+1$$$ distinct colours in the universe, numbered $$$0$$$ through $$$n$$$. There is a strip of paper $$$m$$$ centimetres long initially painted with colour $$$0$$$. Alice took a brush and painted the strip using the following process. For each $$$i$$$ from $$$1$$$ to $$$n$$$, in this order, she picks two integers $$$0 \leq a_i < b_i \leq m$$$, such that the segment $$$[a_i, b_i]$$$ is currently painted with a single colour, and repaints it with colour $$$i$$$. Alice chose the segments in such a way that each centimetre is now painted in some colour other than $$$0$$$. Formally, the segment $$$[i-1, i]$$$ is painted with colour $$$c_i$$$ ($$$c_i \neq 0$$$). Every colour other than $$$0$$$ is visible on the strip.Count the number of different pairs of sequences $$$\{a_i\}_{i=1}^n$$$, $$$\{b_i\}_{i=1}^n$$$ that result in this configuration. Since this number may be large, output it modulo $$$998244353$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"255"Let's denote as L(x, p) an infinite sequence of integers y such that gcd(p, y) = 1 and y > x (where gcd is the greatest common divisor of two integer numbers), sorted in ascending order. The elements of L(x, p) are 1-indexed; for example, 9, 13 and 15 are the first, the second and the third elements of L(7, 22), respectively.You have to process t queries. Each query is denoted by three integers x, p and k, and the answer to this query is k-th element of L(x, p).","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"256Try guessing the statement from this picture:   You are given a non-negative integer $$$d$$$. You have to find two non-negative real numbers $$$a$$$ and $$$b$$$ such that $$$a + b = d$$$ and $$$a \cdot b = d$$$.,['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"257"You are given an array $$$a$$$ consisting of $$$n$$$ integers. You should divide $$$a$$$ into continuous non-empty subarrays (there are $$$2^{n-1}$$$ ways to do that).Let $$$s=a_l+a_{l+1}+\ldots+a_r$$$. The value of a subarray $$$a_l, a_{l+1}, \ldots, a_r$$$ is:   $$$(r-l+1)$$$ if $$$s>0$$$, $$$0$$$ if $$$s=0$$$, $$$-(r-l+1)$$$ if $$$s<0$$$.  What is the maximum sum of values you can get with a partition?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"258"The semester is already ending, so Danil made an effort and decided to visit a lesson on harmony analysis to know how does the professor look like, at least. Danil was very bored on this lesson until the teacher gave the group a simple task: find 4 vectors in 4-dimensional space, such that every coordinate of every vector is 1 or  - 1 and any two vectors are orthogonal. Just as a reminder, two vectors in n-dimensional space are considered to be orthogonal if and only if their scalar product is equal to zero, that is: .Danil quickly managed to come up with the solution for this problem and the teacher noticed that the problem can be solved in a more general case for 2k vectors in 2k-dimensinoal space. When Danil came home, he quickly came up with the solution for this problem. Can you cope with it?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"259"A dice is a cube, its faces contain distinct integers from 1 to 6 as black points. The sum of numbers at the opposite dice faces always equals 7. Please note that there are only two dice (these dices are mirror of each other) that satisfy the given constraints (both of them are shown on the picture on the left).  Alice and Bob play dice. Alice has built a tower from n dice. We know that in this tower the adjacent dice contact with faces with distinct numbers. Bob wants to uniquely identify the numbers written on the faces of all dice, from which the tower is built. Unfortunately, Bob is looking at the tower from the face, and so he does not see all the numbers on the faces. Bob sees the number on the top of the tower and the numbers on the two adjacent sides (on the right side of the picture shown what Bob sees).Help Bob, tell whether it is possible to uniquely identify the numbers on the faces of all the dice in the tower, or not.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"260"Vivek has encountered a problem. He has a maze that can be represented as an $$$n \times m$$$ grid. Each of the grid cells may represent the following:  Empty — '.'  Wall — '#'  Good person  — 'G'  Bad person — 'B' The only escape from the maze is at cell $$$(n, m)$$$.A person can move to a cell only if it shares a side with their current cell and does not contain a wall. Vivek wants to block some of the empty cells by replacing them with walls in such a way, that all the good people are able to escape, while none of the bad people are able to. A cell that initially contains 'G' or 'B' cannot be blocked and can be travelled through.Help him determine if there exists a way to replace some (zero or more) empty cells with walls to satisfy the above conditions.It is guaranteed that the cell $$$(n,m)$$$ is empty. Vivek can also block this cell.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"261"You are given a weighted tree consisting of $$$n$$$ vertices. Recall that a tree is a connected graph without cycles. Vertices $$$u_i$$$ and $$$v_i$$$ are connected by an edge with weight $$$w_i$$$.You are given $$$m$$$ queries. The $$$i$$$-th query is given as an integer $$$q_i$$$. In this query you need to calculate the number of pairs of vertices $$$(u, v)$$$ ($$$u < v$$$) such that the maximum weight of an edge on a simple path between $$$u$$$ and $$$v$$$ doesn't exceed $$$q_i$$$.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"262"Ehab has an array $$$a$$$ of length $$$n$$$. He has just enough free time to make a new array consisting of $$$n$$$ copies of the old array, written back-to-back. What will be the length of the new array's longest increasing subsequence?A sequence $$$a$$$ is a subsequence of an array $$$b$$$ if $$$a$$$ can be obtained from $$$b$$$ by deletion of several (possibly, zero or all) elements. The longest increasing subsequence of an array is the longest subsequence such that its elements are ordered in strictly increasing order.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"263"Eudokimus, a system administrator is in trouble again. As a result of an error in some script, a list of names of very important files has been damaged. Since they were files in the BerFS file system, it is known that each file name has a form ""name.ext"", where:   name is a string consisting of lowercase Latin letters, its length is from 1 to 8 characters;  ext is a string consisting of lowercase Latin letters, its length is from 1 to 3 characters. For example, ""read.me"", ""example.txt"" and ""b.cpp"" are valid file names and ""version.info"", ""ntldr"" and ""contestdata.zip"" are not.Damage to the list meant that all the file names were recorded one after another, without any separators. So now Eudokimus has a single string.Eudokimus needs to set everything right as soon as possible. He should divide the resulting string into parts so that each part would be a valid file name in BerFS. Since Eudokimus has already proved that he is not good at programming, help him. The resulting file list can contain the same file names.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"264You are given n points on a plane. All the points are distinct and no three of them lie on the same line. Find the number of parallelograms with the vertices at the given points.,['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"265"You are given an undirected graph consisting of $$$n$$$ vertices and $$$m$$$ edges. Your task is to find the number of connected components which are cycles.Here are some definitions of graph theory.An undirected graph consists of two sets: set of nodes (called vertices) and set of edges. Each edge connects a pair of vertices. All edges are bidirectional (i.e. if a vertex $$$a$$$ is connected with a vertex $$$b$$$, a vertex $$$b$$$ is also connected with a vertex $$$a$$$). An edge can't connect vertex with itself, there is at most one edge between a pair of vertices.Two vertices $$$u$$$ and $$$v$$$ belong to the same connected component if and only if there is at least one path along edges connecting $$$u$$$ and $$$v$$$.A connected component is a cycle if and only if its vertices can be reordered in such a way that:  the first vertex is connected with the second vertex by an edge,  the second vertex is connected with the third vertex by an edge,  ...  the last vertex is connected with the first vertex by an edge,  all the described edges of a cycle are distinct. A cycle doesn't contain any other edges except described above. By definition any cycle contains three or more vertices.    There are $$$6$$$ connected components, $$$2$$$ of them are cycles: $$$[7, 10, 16]$$$ and $$$[5, 11, 9, 15]$$$. ",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"266"Alice gave Bob two integers $$$a$$$ and $$$b$$$ ($$$a > 0$$$ and $$$b \ge 0$$$). Being a curious boy, Bob wrote down an array of non-negative integers with $$$\operatorname{MEX}$$$ value of all elements equal to $$$a$$$ and $$$\operatorname{XOR}$$$ value of all elements equal to $$$b$$$.What is the shortest possible length of the array Bob wrote?Recall that the $$$\operatorname{MEX}$$$ (Minimum EXcluded) of an array is the minimum non-negative integer that does not belong to the array and the $$$\operatorname{XOR}$$$ of an array is the bitwise XOR of all the elements of the array.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"267"Little town Nsk consists of n junctions connected by m bidirectional roads. Each road connects two distinct junctions and no two roads connect the same pair of junctions. It is possible to get from any junction to any other junction by these roads. The distance between two junctions is equal to the minimum possible number of roads on a path between them.In order to improve the transportation system, the city council asks mayor to build one new road. The problem is that the mayor has just bought a wonderful new car and he really enjoys a ride from his home, located near junction s to work located near junction t. Thus, he wants to build a new road in such a way that the distance between these two junctions won't decrease. You are assigned a task to compute the number of pairs of junctions that are not connected by the road, such that if the new road between these two junctions is built the distance between s and t won't decrease.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"268"Ayrat has number n, represented as it's prime factorization pi of size m, i.e. n = p1·p2·...·pm. Ayrat got secret information that that the product of all divisors of n taken modulo 109 + 7 is the password to the secret data base. Now he wants to calculate this value.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"269"You have matrix a of size n × n. Let's number the rows of the matrix from 1 to n from top to bottom, let's number the columns from 1 to n from left to right. Let's use aij to represent the element on the intersection of the i-th row and the j-th column. Matrix a meets the following two conditions:   for any numbers i, j (1 ≤ i, j ≤ n) the following inequality holds: aij ≥ 0;  . Matrix b is strictly positive, if for any numbers i, j (1 ≤ i, j ≤ n) the inequality bij > 0 holds. You task is to determine if there is such integer k ≥ 1, that matrix ak is strictly positive.","['graphs', 'math']","[0, 0, 1, 1, 0, 0, 0, 0]"270"For a vector $$$\vec{v} = (x, y)$$$, define $$$|v| = \sqrt{x^2 + y^2}$$$.Allen had a bit too much to drink at the bar, which is at the origin. There are $$$n$$$ vectors $$$\vec{v_1}, \vec{v_2}, \cdots, \vec{v_n}$$$. Allen will make $$$n$$$ moves. As Allen's sense of direction is impaired, during the $$$i$$$-th move he will either move in the direction $$$\vec{v_i}$$$ or $$$-\vec{v_i}$$$. In other words, if his position is currently $$$p = (x, y)$$$, he will either move to $$$p + \vec{v_i}$$$ or $$$p - \vec{v_i}$$$.Allen doesn't want to wander too far from home (which happens to also be the bar). You need to help him figure out a sequence of moves (a sequence of signs for the vectors) such that his final position $$$p$$$ satisfies $$$|p| \le 1.5 \cdot 10^6$$$ so that he can stay safe.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"271"Marina loves strings of the same length and Vasya loves when there is a third string, different from them in exactly t characters. Help Vasya find at least one such string.More formally, you are given two strings s1, s2 of length n and number t. Let's denote as f(a, b) the number of characters in which strings a and b are different. Then your task will be to find any string s3 of length n, such that f(s1, s3) = f(s2, s3) = t. If there is no such string, print  - 1.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"272" Morning desert sun horizonRise above the sands of time...Fates Warning, ""Exodus""After crossing the Windswept Wastes, Ori has finally reached the Windtorn Ruins to find the Heart of the Forest! However, the ancient repository containing this priceless Willow light did not want to open!Ori was taken aback, but the Voice of the Forest explained to him that the cunning Gorleks had decided to add protection to the repository.The Gorleks were very fond of the ""string expansion"" operation. They were also very fond of increasing subsequences.Suppose a string $$$s_1s_2s_3 \ldots s_n$$$ is given. Then its ""expansion"" is defined as the sequence of strings $$$s_1$$$, $$$s_1 s_2$$$, ..., $$$s_1 s_2 \ldots s_n$$$, $$$s_2$$$, $$$s_2 s_3$$$, ..., $$$s_2 s_3 \ldots s_n$$$, $$$s_3$$$, $$$s_3 s_4$$$, ..., $$$s_{n-1} s_n$$$, $$$s_n$$$. For example, the ""expansion"" the string 'abcd' will be the following sequence of strings: 'a', 'ab', 'abc', 'abcd', 'b', 'bc', 'bcd', 'c', 'cd', 'd'. To open the ancient repository, Ori must find the size of the largest increasing subsequence of the ""expansion"" of the string $$$s$$$. Here, strings are compared lexicographically.Help Ori with this task!A string $$$a$$$ is lexicographically smaller than a string $$$b$$$ if and only if one of the following holds: $$$a$$$ is a prefix of $$$b$$$, but $$$a \ne b$$$; in the first position where $$$a$$$ and $$$b$$$ differ, the string $$$a$$$ has a letter that appears earlier in the alphabet than the corresponding letter in $$$b$$$.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"273"Valera takes part in the Berland Marathon. The marathon race starts at the stadium that can be represented on the plane as a square whose lower left corner is located at point with coordinates (0, 0) and the length of the side equals a meters. The sides of the square are parallel to coordinate axes.As the length of the marathon race is very long, Valera needs to have extra drink during the race. The coach gives Valera a bottle of drink each d meters of the path. We know that Valera starts at the point with coordinates (0, 0) and runs counter-clockwise. That is, when Valera covers a meters, he reaches the point with coordinates (a, 0). We also know that the length of the marathon race equals nd + 0.5 meters. Help Valera's coach determine where he should be located to help Valera. Specifically, determine the coordinates of Valera's positions when he covers d, 2·d, ..., n·d meters.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"274"This is the first subtask of problem F. The only differences between this and the second subtask are the constraints on the value of $$$m$$$ and the time limit. You need to solve both subtasks in order to hack this one.There are $$$n+1$$$ distinct colours in the universe, numbered $$$0$$$ through $$$n$$$. There is a strip of paper $$$m$$$ centimetres long initially painted with colour $$$0$$$. Alice took a brush and painted the strip using the following process. For each $$$i$$$ from $$$1$$$ to $$$n$$$, in this order, she picks two integers $$$0 \leq a_i < b_i \leq m$$$, such that the segment $$$[a_i, b_i]$$$ is currently painted with a single colour, and repaints it with colour $$$i$$$. Alice chose the segments in such a way that each centimetre is now painted in some colour other than $$$0$$$. Formally, the segment $$$[i-1, i]$$$ is painted with colour $$$c_i$$$ ($$$c_i \neq 0$$$). Every colour other than $$$0$$$ is visible on the strip.Count the number of different pairs of sequences $$$\{a_i\}_{i=1}^n$$$, $$$\{b_i\}_{i=1}^n$$$ that result in this configuration. Since this number may be large, output it modulo $$$998244353$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"275"Authors have come up with the string $$$s$$$ consisting of $$$n$$$ lowercase Latin letters.You are given two permutations of its indices (not necessary equal) $$$p$$$ and $$$q$$$ (both of length $$$n$$$). Recall that the permutation is the array of length $$$n$$$ which contains each integer from $$$1$$$ to $$$n$$$ exactly once.For all $$$i$$$ from $$$1$$$ to $$$n-1$$$ the following properties hold: $$$s[p_i] \le s[p_{i + 1}]$$$ and $$$s[q_i] \le s[q_{i + 1}]$$$. It means that if you will write down all characters of $$$s$$$ in order of permutation indices, the resulting string will be sorted in the non-decreasing order.Your task is to restore any such string $$$s$$$ of length $$$n$$$ consisting of at least $$$k$$$ distinct lowercase Latin letters which suits the given permutations.If there are multiple answers, you can print any of them.","['graphs', 'strings']","[0, 0, 1, 0, 0, 0, 1, 0]"276"You have two strings $$$s_1$$$ and $$$s_2$$$ of length $$$n$$$, consisting of lowercase English letters. You can perform the following operation any (possibly zero) number of times:   Choose a positive integer $$$1 \leq k \leq n$$$.  Swap the prefix of the string $$$s_1$$$ and the suffix of the string $$$s_2$$$ of length $$$k$$$. Is it possible to make these two strings equal by doing described operations?",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"277"You are given $$$n$$$ segments on a coordinate line; each endpoint of every segment has integer coordinates. Some segments can degenerate to points. Segments can intersect with each other, be nested in each other or even coincide.Your task is the following: for every $$$k \in [1..n]$$$, calculate the number of points with integer coordinates such that the number of segments that cover these points equals $$$k$$$. A segment with endpoints $$$l_i$$$ and $$$r_i$$$ covers point $$$x$$$ if and only if $$$l_i \le x \le r_i$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"278"You are given a book with $$$n$$$ chapters.Each chapter has a specified list of other chapters that need to be understood in order to understand this chapter. To understand a chapter, you must read it after you understand every chapter on its required list.Currently you don't understand any of the chapters. You are going to read the book from the beginning till the end repeatedly until you understand the whole book. Note that if you read a chapter at a moment when you don't understand some of the required chapters, you don't understand this chapter.Determine how many times you will read the book to understand every chapter, or determine that you will never understand every chapter no matter how many times you read the book.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"279"Vasya has n days of vacations! So he decided to improve his IT skills and do sport. Vasya knows the following information about each of this n days: whether that gym opened and whether a contest was carried out in the Internet on that day. For the i-th day there are four options:  on this day the gym is closed and the contest is not carried out;  on this day the gym is closed and the contest is carried out;  on this day the gym is open and the contest is not carried out;  on this day the gym is open and the contest is carried out. On each of days Vasya can either have a rest or write the contest (if it is carried out on this day), or do sport (if the gym is open on this day).Find the minimum number of days on which Vasya will have a rest (it means, he will not do sport and write the contest at the same time). The only limitation that Vasya has — he does not want to do the same activity on two consecutive days: it means, he will not do sport on two consecutive days, and write the contest on two consecutive days.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"280"The Fair Nut likes kvass very much. On his birthday parents presented him $$$n$$$ kegs of kvass. There are $$$v_i$$$ liters of kvass in the $$$i$$$-th keg. Each keg has a lever. You can pour your glass by exactly $$$1$$$ liter pulling this lever. The Fair Nut likes this drink very much, so he wants to pour his glass by $$$s$$$ liters of kvass. But he wants to do it, so kvass level in the least keg is as much as possible.Help him find out how much kvass can be in the least keg or define it's not possible to pour his glass by $$$s$$$ liters of kvass.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"281"You are given a grid, consisting of $$$2$$$ rows and $$$n$$$ columns. Each cell of this grid should be colored either black or white.Two cells are considered neighbours if they have a common border and share the same color. Two cells $$$A$$$ and $$$B$$$ belong to the same component if they are neighbours, or if there is a neighbour of $$$A$$$ that belongs to the same component with $$$B$$$.Let's call some bicoloring beautiful if it has exactly $$$k$$$ components.Count the number of beautiful bicolorings. The number can be big enough, so print the answer modulo $$$998244353$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"282"This is an interactive problem.Homer likes arrays a lot and he wants to play a game with you. Homer has hidden from you a permutation $$$a_1, a_2, \dots, a_n$$$ of integers $$$1$$$ to $$$n$$$. You are asked to find any index $$$k$$$ ($$$1 \leq k \leq n$$$) which is a local minimum. For an array $$$a_1, a_2, \dots, a_n$$$, an index $$$i$$$ ($$$1 \leq i \leq n$$$) is said to be a local minimum if $$$a_i < \min\{a_{i-1},a_{i+1}\}$$$, where $$$a_0 = a_{n+1} = +\infty$$$. An array is said to be a permutation of integers $$$1$$$ to $$$n$$$, if it contains all integers from $$$1$$$ to $$$n$$$ exactly once.Initially, you are only given the value of $$$n$$$ without any other information about this permutation.At each interactive step, you are allowed to choose any $$$i$$$ ($$$1 \leq i \leq n$$$) and make a query with it. As a response, you will be given the value of $$$a_i$$$. You are asked to find any index $$$k$$$ which is a local minimum after at most $$$100$$$ queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"283"Alexey, a merry Berland entrant, got sick of the gray reality and he zealously wants to go to university. There are a lot of universities nowadays, so Alexey is getting lost in the diversity — he has not yet decided what profession he wants to get. At school, he had bad grades in all subjects, and it's only thanks to wealthy parents that he was able to obtain the graduation certificate.The situation is complicated by the fact that each high education institution has the determined amount of voluntary donations, paid by the new students for admission — ni berubleys. He cannot pay more than ni, because then the difference between the paid amount and ni can be regarded as a bribe!Each rector is wearing the distinctive uniform of his university. Therefore, the uniform's pockets cannot contain coins of denomination more than ri. The rector also does not carry coins of denomination less than li in his pocket — because if everyone pays him with so small coins, they gather a lot of weight and the pocket tears. Therefore, a donation can be paid only by coins of denomination x berubleys, where li ≤ x ≤ ri (Berland uses coins of any positive integer denomination). Alexey can use the coins of different denominations and he can use the coins of the same denomination any number of times. When Alexey was first confronted with such orders, he was puzzled because it turned out that not all universities can accept him! Alexey is very afraid of going into the army (even though he had long wanted to get the green uniform, but his dad says that the army bullies will beat his son and he cannot pay to ensure the boy's safety). So, Alexey wants to know for sure which universities he can enter so that he could quickly choose his alma mater.Thanks to the parents, Alexey is not limited in money and we can assume that he has an unlimited number of coins of each type.In other words, you are given t requests, each of them contains numbers ni, li, ri. For each query you need to answer, whether it is possible to gather the sum of exactly ni berubleys using only coins with an integer denomination from li to ri berubleys. You can use coins of different denominations. Coins of each denomination can be used any number of times.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"284"You are given a multiset (i. e. a set that can contain multiple equal integers) containing $$$2n$$$ integers. Determine if you can split it into exactly $$$n$$$ pairs (i. e. each element should be in exactly one pair) so that the sum of the two elements in each pair is odd (i. e. when divided by $$$2$$$, the remainder is $$$1$$$).",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"285"Sasha grew up and went to first grade. To celebrate this event her mother bought her a multiplication table $$$M$$$ with $$$n$$$ rows and $$$n$$$ columns such that $$$M_{ij}=a_i \cdot a_j$$$ where $$$a_1, \dots, a_n$$$ is some sequence of positive integers.Of course, the girl decided to take it to school with her. But while she was having lunch, hooligan Grisha erased numbers on the main diagonal and threw away the array $$$a_1, \dots, a_n$$$. Help Sasha restore the array!","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"286"Petya is the most responsible worker in the Research Institute. So he was asked to make a very important experiment: to melt the chocolate bar with a new laser device. The device consists of a rectangular field of n × m cells and a robotic arm. Each cell of the field is a 1 × 1 square. The robotic arm has two lasers pointed at the field perpendicularly to its surface. At any one time lasers are pointed at the centres of some two cells. Since the lasers are on the robotic hand, their movements are synchronized — if you move one of the lasers by a vector, another one moves by the same vector.The following facts about the experiment are known:   initially the whole field is covered with a chocolate bar of the size n × m, both lasers are located above the field and are active;  the chocolate melts within one cell of the field at which the laser is pointed;  all moves of the robotic arm should be parallel to the sides of the field, after each move the lasers should be pointed at the centres of some two cells;  at any one time both lasers should be pointed at the field. Petya doesn't want to become a second Gordon Freeman. You are given n, m and the cells (x1, y1) and (x2, y2), where the lasers are initially pointed at (xi is a column number, yi is a row number). Rows are numbered from 1 to m from top to bottom and columns are numbered from 1 to n from left to right. You are to find the amount of cells of the field on which the chocolate can't be melted in the given conditions.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"287"You all know that the Library of Bookland is the largest library in the world. There are dozens of thousands of books in the library.Some long and uninteresting story was removed...The alphabet of Bookland is so large that its letters are denoted by positive integers. Each letter can be small or large, the large version of a letter x is denoted by x'. BSCII encoding, which is used everywhere in Bookland, is made in that way so that large letters are presented in the order of the numbers they are denoted by, and small letters are presented in the order of the numbers they are denoted by, but all large letters are before all small letters. For example, the following conditions hold: 2 < 3, 2' < 3', 3' < 2.A word x1, x2, ..., xa is not lexicographically greater than y1, y2, ..., yb if one of the two following conditions holds:   a ≤ b and x1 = y1, ..., xa = ya, i.e. the first word is the prefix of the second word;  there is a position 1 ≤ j ≤ min(a, b), such that x1 = y1, ..., xj - 1 = yj - 1 and xj < yj, i.e. at the first position where the words differ the first word has a smaller letter than the second word has.  For example, the word ""3' 7 5"" is before the word ""2 4' 6"" in lexicographical order. It is said that sequence of words is in lexicographical order if each word is not lexicographically greater than the next word in the sequence.Denis has a sequence of words consisting of small letters only. He wants to change some letters to large (let's call this process a capitalization) in such a way that the sequence of words is in lexicographical order. However, he soon realized that for some reason he can't change a single letter in a single word. He only can choose a letter and change all of its occurrences in all words to large letters. He can perform this operation any number of times with arbitrary letters of Bookland's alphabet.Help Denis to choose which letters he needs to capitalize (make large) in order to make the sequence of words lexicographically ordered, or determine that it is impossible.Note that some words can be equal.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"288"In the game of Mastermind, there are two players  — Alice and Bob. Alice has a secret code, which Bob tries to guess. Here, a code is defined as a sequence of $$$n$$$ colors. There are exactly $$$n+1$$$ colors in the entire universe, numbered from $$$1$$$ to $$$n+1$$$ inclusive.When Bob guesses a code, Alice tells him some information about how good of a guess it is, in the form of two integers $$$x$$$ and $$$y$$$.The first integer $$$x$$$ is the number of indices where Bob's guess correctly matches Alice's code. The second integer $$$y$$$ is the size of the intersection of the two codes as multisets. That is, if Bob were to change the order of the colors in his guess, $$$y$$$ is the maximum number of indices he could get correct.For example, suppose $$$n=5$$$, Alice's code is $$$[3,1,6,1,2]$$$, and Bob's guess is $$$[3,1,1,2,5]$$$. At indices $$$1$$$ and $$$2$$$ colors are equal, while in the other indices they are not equal. So $$$x=2$$$. And the two codes have the four colors $$$1,1,2,3$$$ in common, so $$$y=4$$$.  Solid lines denote a matched color for the same index. Dashed lines denote a matched color at a different index. $$$x$$$ is the number of solid lines, and $$$y$$$ is the total number of lines. You are given Bob's guess and two values $$$x$$$ and $$$y$$$. Can you find one possibility of Alice's code so that the values of $$$x$$$ and $$$y$$$ are correct?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"289"It is nighttime and Joe the Elusive got into the country's main bank's safe. The safe has n cells positioned in a row, each of them contains some amount of diamonds. Let's make the problem more comfortable to work with and mark the cells with positive numbers from 1 to n from the left to the right.Unfortunately, Joe didn't switch the last security system off. On the plus side, he knows the way it works.Every minute the security system calculates the total amount of diamonds for each two adjacent cells (for the cells between whose numbers difference equals 1). As a result of this check we get an n - 1 sums. If at least one of the sums differs from the corresponding sum received during the previous check, then the security system is triggered.Joe can move the diamonds from one cell to another between the security system's checks. He manages to move them no more than m times between two checks. One of the three following operations is regarded as moving a diamond: moving a diamond from any cell to any other one, moving a diamond from any cell to Joe's pocket, moving a diamond from Joe's pocket to any cell. Initially Joe's pocket is empty, and it can carry an unlimited amount of diamonds. It is considered that before all Joe's actions the system performs at least one check.In the morning the bank employees will come, which is why Joe has to leave the bank before that moment. Joe has only k minutes left before morning, and on each of these k minutes he can perform no more than m operations. All that remains in Joe's pocket, is considered his loot.Calculate the largest amount of diamonds Joe can carry with him. Don't forget that the security system shouldn't be triggered (even after Joe leaves the bank) and Joe should leave before morning.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"290"You had $$$n$$$ positive integers $$$a_1, a_2, \dots, a_n$$$ arranged in a circle. For each pair of neighboring numbers ($$$a_1$$$ and $$$a_2$$$, $$$a_2$$$ and $$$a_3$$$, ..., $$$a_{n - 1}$$$ and $$$a_n$$$, and $$$a_n$$$ and $$$a_1$$$), you wrote down: are the numbers in the pair equal or not.Unfortunately, you've lost a piece of paper with the array $$$a$$$. Moreover, you are afraid that even information about equality of neighboring elements may be inconsistent. So, you are wondering: is there any array $$$a$$$ which is consistent with information you have about equality or non-equality of corresponding pairs?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"291"Leha decided to move to a quiet town Vičkopolis, because he was tired by living in Bankopolis. Upon arrival he immediately began to expand his network of hacked computers. During the week Leha managed to get access to n computers throughout the town. Incidentally all the computers, which were hacked by Leha, lie on the same straight line, due to the reason that there is the only one straight street in Vičkopolis.Let's denote the coordinate system on this street. Besides let's number all the hacked computers with integers from 1 to n. So the i-th hacked computer is located at the point xi. Moreover the coordinates of all computers are distinct. Leha is determined to have a little rest after a hard week. Therefore he is going to invite his friend Noora to a restaurant. However the girl agrees to go on a date with the only one condition: Leha have to solve a simple task.Leha should calculate a sum of F(a) for all a, where a is a non-empty subset of the set, that consists of all hacked computers. Formally, let's denote A the set of all integers from 1 to n. Noora asks the hacker to find value of the expression . Here F(a) is calculated as the maximum among the distances between all pairs of computers from the set a. Formally, . Since the required sum can be quite large Noora asks to find it modulo 109 + 7.Though, Leha is too tired. Consequently he is not able to solve this task. Help the hacker to attend a date.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"292"New Year is coming! Vasya has prepared a New Year's verse and wants to recite it in front of Santa Claus.Vasya's verse contains $$$n$$$ parts. It takes $$$a_i$$$ seconds to recite the $$$i$$$-th part. Vasya can't change the order of parts in the verse: firstly he recites the part which takes $$$a_1$$$ seconds, secondly — the part which takes $$$a_2$$$ seconds, and so on. After reciting the verse, Vasya will get the number of presents equal to the number of parts he fully recited.Vasya can skip at most one part of the verse while reciting it (if he skips more than one part, then Santa will definitely notice it).Santa will listen to Vasya's verse for no more than $$$s$$$ seconds. For example, if $$$s = 10$$$, $$$a = [100, 9, 1, 1]$$$, and Vasya skips the first part of verse, then he gets two presents.Note that it is possible to recite the whole verse (if there is enough time). Determine which part Vasya needs to skip to obtain the maximum possible number of gifts. If Vasya shouldn't skip anything, print 0. If there are multiple answers, print any of them.You have to process $$$t$$$ test cases.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"293"Monocarp and Polycarp are learning new programming techniques. Now they decided to try pair programming.It's known that they have worked together on the same file for $$$n + m$$$ minutes. Every minute exactly one of them made one change to the file. Before they started, there were already $$$k$$$ lines written in the file.Every minute exactly one of them does one of two actions: adds a new line to the end of the file or changes one of its lines.Monocarp worked in total for $$$n$$$ minutes and performed the sequence of actions $$$[a_1, a_2, \dots, a_n]$$$. If $$$a_i = 0$$$, then he adds a new line to the end of the file. If $$$a_i > 0$$$, then he changes the line with the number $$$a_i$$$. Monocarp performed actions strictly in this order: $$$a_1$$$, then $$$a_2$$$, ..., $$$a_n$$$.Polycarp worked in total for $$$m$$$ minutes and performed the sequence of actions $$$[b_1, b_2, \dots, b_m]$$$. If $$$b_j = 0$$$, then he adds a new line to the end of the file. If $$$b_j > 0$$$, then he changes the line with the number $$$b_j$$$. Polycarp performed actions strictly in this order: $$$b_1$$$, then $$$b_2$$$, ..., $$$b_m$$$.Restore their common sequence of actions of length $$$n + m$$$ such that all actions would be correct — there should be no changes to lines that do not yet exist. Keep in mind that in the common sequence Monocarp's actions should form the subsequence $$$[a_1, a_2, \dots, a_n]$$$ and Polycarp's — subsequence $$$[b_1, b_2, \dots, b_m]$$$. They can replace each other at the computer any number of times.Let's look at an example. Suppose $$$k = 3$$$. Monocarp first changed the line with the number $$$2$$$ and then added a new line (thus, $$$n = 2, \: a = [2, 0]$$$). Polycarp first added a new line and then changed the line with the number $$$5$$$ (thus, $$$m = 2, \: b = [0, 5]$$$).Since the initial length of the file was $$$3$$$, in order for Polycarp to change line number $$$5$$$ two new lines must be added beforehand. Examples of correct sequences of changes, in this case, would be $$$[0, 2, 0, 5]$$$ and $$$[2, 0, 0, 5]$$$. Changes $$$[0, 0, 5, 2]$$$ (wrong order of actions) and $$$[0, 5, 2, 0]$$$ (line $$$5$$$ cannot be edited yet) are not correct.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"294"Fox Ciel is playing a mobile puzzle game called ""Two Dots"". The basic levels are played on a board of size n × m cells, like this:Each cell contains a dot that has some color. We will use different uppercase Latin characters to express different colors.The key of this game is to find a cycle that contain dots of same color. Consider 4 blue dots on the picture forming a circle as an example. Formally, we call a sequence of dots d1, d2, ..., dk a cycle if and only if it meets the following condition:  These k dots are different: if i ≠ j then di is different from dj.  k is at least 4.  All dots belong to the same color.  For all 1 ≤ i ≤ k - 1: di and di + 1 are adjacent. Also, dk and d1 should also be adjacent. Cells x and y are called adjacent if they share an edge. Determine if there exists a cycle on the field.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"295"You have array a1, a2, ..., an. Segment [l, r] (1 ≤ l ≤ r ≤ n) is good if ai = ai - 1 + ai - 2, for all i (l + 2 ≤ i ≤ r).Let's define len([l, r]) = r - l + 1, len([l, r]) is the length of the segment [l, r]. Segment [l1, r1], is longer than segment [l2, r2], if len([l1, r1]) > len([l2, r2]).Your task is to find a good segment of the maximum length in array a. Note that a segment of length 1 or 2 is always good.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"296"Timur likes his name. As a spelling of his name, he allows any permutation of the letters of the name. For example, the following strings are valid spellings of his name: Timur, miurT, Trumi, mriTu. Note that the correct spelling must have uppercased T and lowercased other letters.Today he wrote string $$$s$$$ of length $$$n$$$ consisting only of uppercase or lowercase Latin letters. He asks you to check if $$$s$$$ is the correct spelling of his name.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"297"Watchmen are in a danger and Doctor Manhattan together with his friend Daniel Dreiberg should warn them as soon as possible. There are n watchmen on a plane, the i-th watchman is located at point (xi, yi).They need to arrange a plan, but there are some difficulties on their way. As you know, Doctor Manhattan considers the distance between watchmen i and j to be |xi - xj| + |yi - yj|. Daniel, as an ordinary person, calculates the distance using the formula .The success of the operation relies on the number of pairs (i, j) (1 ≤ i < j ≤ n), such that the distance between watchman i and watchmen j calculated by Doctor Manhattan is equal to the distance between them calculated by Daniel. You were asked to compute the number of such pairs.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"298"You are given a sequence $$$a$$$ consisting of $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$, and an integer $$$x$$$. Your task is to make the sequence $$$a$$$ sorted (it is considered sorted if the condition $$$a_1 \le a_2 \le a_3 \le \dots \le a_n$$$ holds).To make the sequence sorted, you may perform the following operation any number of times you want (possibly zero): choose an integer $$$i$$$ such that $$$1 \le i \le n$$$ and $$$a_i > x$$$, and swap the values of $$$a_i$$$ and $$$x$$$.For example, if $$$a = [0, 2, 3, 5, 4]$$$, $$$x = 1$$$, the following sequence of operations is possible:  choose $$$i = 2$$$ (it is possible since $$$a_2 > x$$$), then $$$a = [0, 1, 3, 5, 4]$$$, $$$x = 2$$$;  choose $$$i = 3$$$ (it is possible since $$$a_3 > x$$$), then $$$a = [0, 1, 2, 5, 4]$$$, $$$x = 3$$$;  choose $$$i = 4$$$ (it is possible since $$$a_4 > x$$$), then $$$a = [0, 1, 2, 3, 4]$$$, $$$x = 5$$$. Calculate the minimum number of operations you have to perform so that $$$a$$$ becomes sorted, or report that it is impossible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"299"You are given an array a consisting of n elements. The imbalance value of some subsegment of this array is the difference between the maximum and minimum element from this segment. The imbalance value of the array is the sum of imbalance values of all subsegments of this array.For example, the imbalance value of array [1, 4, 1] is 9, because there are 6 different subsegments of this array:   [1] (from index 1 to index 1), imbalance value is 0;  [1, 4] (from index 1 to index 2), imbalance value is 3;  [1, 4, 1] (from index 1 to index 3), imbalance value is 3;  [4] (from index 2 to index 2), imbalance value is 0;  [4, 1] (from index 2 to index 3), imbalance value is 3;  [1] (from index 3 to index 3), imbalance value is 0; You have to determine the imbalance value of the array a.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"300"The only difference between easy and hard versions is constraints.You are given a sequence $$$a$$$ consisting of $$$n$$$ positive integers.Let's define a three blocks palindrome as the sequence, consisting of at most two distinct elements (let these elements are $$$a$$$ and $$$b$$$, $$$a$$$ can be equal $$$b$$$) and is as follows: $$$[\underbrace{a, a, \dots, a}_{x}, \underbrace{b, b, \dots, b}_{y}, \underbrace{a, a, \dots, a}_{x}]$$$. There $$$x, y$$$ are integers greater than or equal to $$$0$$$. For example, sequences $$$[]$$$, $$$[2]$$$, $$$[1, 1]$$$, $$$[1, 2, 1]$$$, $$$[1, 2, 2, 1]$$$ and $$$[1, 1, 2, 1, 1]$$$ are three block palindromes but $$$[1, 2, 3, 2, 1]$$$, $$$[1, 2, 1, 2, 1]$$$ and $$$[1, 2]$$$ are not.Your task is to choose the maximum by length subsequence of $$$a$$$ that is a three blocks palindrome.You have to answer $$$t$$$ independent test cases.Recall that the sequence $$$t$$$ is a a subsequence of the sequence $$$s$$$ if $$$t$$$ can be derived from $$$s$$$ by removing zero or more elements without changing the order of the remaining elements. For example, if $$$s=[1, 2, 1, 3, 1, 2, 1]$$$, then possible subsequences are: $$$[1, 1, 1, 1]$$$, $$$[3]$$$ and $$$[1, 2, 1, 3, 1, 2, 1]$$$, but not $$$[3, 2, 3]$$$ and $$$[1, 1, 1, 1, 2]$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"301"You are given two arrays of integers $$$a_1,\ldots,a_n$$$ and $$$b_1,\ldots,b_m$$$.Your task is to find a non-empty array $$$c_1,\ldots,c_k$$$ that is a subsequence of $$$a_1,\ldots,a_n$$$, and also a subsequence of $$$b_1,\ldots,b_m$$$. If there are multiple answers, find one of the smallest possible length. If there are still multiple of the smallest possible length, find any. If there are no such arrays, you should report about it.A sequence $$$a$$$ is a subsequence of a sequence $$$b$$$ if $$$a$$$ can be obtained from $$$b$$$ by deletion of several (possibly, zero) elements. For example, $$$[3,1]$$$ is a subsequence of $$$[3,2,1]$$$ and $$$[4,3,1]$$$, but not a subsequence of $$$[1,3,3,7]$$$ and $$$[3,10,4]$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"302"One day Polycarpus stopped by a supermarket on his way home. It turns out that the supermarket is having a special offer for stools. The offer is as follows: if a customer's shopping cart contains at least one stool, the customer gets a 50% discount on the cheapest item in the cart (that is, it becomes two times cheaper). If there are several items with the same minimum price, the discount is available for only one of them!Polycarpus has k carts, and he wants to buy up all stools and pencils from the supermarket. Help him distribute the stools and the pencils among the shopping carts, so that the items' total price (including the discounts) is the least possible.Polycarpus must use all k carts to purchase the items, no shopping cart can remain empty. Each shopping cart can contain an arbitrary number of stools and/or pencils.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"303"Two people play the following string game. Initially the players have got some string s. The players move in turns, the player who cannot make a move loses. Before the game began, the string is written on a piece of paper, one letter per cell.  An example of the initial situation at s = ""abacaba"" A player's move is the sequence of actions:  The player chooses one of the available pieces of paper with some string written on it. Let's denote it is t. Note that initially, only one piece of paper is available.  The player chooses in the string t = t1t2... t|t| character in position i (1 ≤ i ≤ |t|) such that for some positive integer l (0 < i - l; i + l ≤ |t|) the following equations hold: ti - 1 = ti + 1, ti - 2 = ti + 2, ..., ti - l = ti + l.  Player cuts the cell with the chosen character. As a result of the operation, he gets three new pieces of paper, the first one will contain string t1t2... ti - 1, the second one will contain a string consisting of a single character ti, the third one contains string ti + 1ti + 2... t|t|.   An example of making action (i = 4) with string s = «abacaba» Your task is to determine the winner provided that both players play optimally well. If the first player wins, find the position of character that is optimal to cut in his first move. If there are multiple positions, print the minimal possible one.",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"304"Bessie and the cows are playing with sequences and need your help. They start with a sequence, initially containing just the number 0, and perform n operations. Each operation is one of the following:  Add the integer xi to the first ai elements of the sequence.  Append an integer ki to the end of the sequence. (And hence the size of the sequence increases by 1)  Remove the last element of the sequence. So, the size of the sequence decreases by one. Note, that this operation can only be done if there are at least two elements in the sequence. After each operation, the cows would like to know the average of all the numbers in the sequence. Help them!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"305"During a New Year special offer the ""Sudislavl Bars"" offered n promo codes. Each promo code consists of exactly six digits and gives right to one free cocktail at the bar ""Mosquito Shelter"". Of course, all the promocodes differ.As the ""Mosquito Shelter"" opens only at 9, and partying in Sudislavl usually begins at as early as 6, many problems may arise as to how to type a promotional code without errors. It is necessary to calculate such maximum k, that the promotional code could be uniquely identified if it was typed with no more than k errors. At that, k = 0 means that the promotional codes must be entered exactly.A mistake in this problem should be considered as entering the wrong numbers. For example, value ""123465"" contains two errors relative to promocode ""123456"". Regardless of the number of errors the entered value consists of exactly six digits.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"306"You have integer $$$n$$$. Calculate how many ways are there to fully cover belt-like area of $$$4n-2$$$ triangles with diamond shapes. Diamond shape consists of two triangles. You can move, rotate or flip the shape, but you cannot scale it. $$$2$$$ coverings are different if some $$$2$$$ triangles are covered by the same diamond shape in one of them and by different diamond shapes in the other one.Please look at pictures below for better understanding.  On the left you can see the diamond shape you will use, and on the right you can see the area you want to fill. These are the figures of the area you want to fill for $$$n = 1, 2, 3, 4$$$. You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"307"The Berland University is preparing to celebrate the 256-th anniversary of its founding! A specially appointed Vice Rector for the celebration prepares to decorate the campus. In the center of the campus n ice sculptures were erected. The sculptures are arranged in a circle at equal distances from each other, so they form a regular n-gon. They are numbered in clockwise order with numbers from 1 to n.The site of the University has already conducted a voting that estimated each sculpture's characteristic of ti — the degree of the sculpture's attractiveness. The values of ti can be positive, negative or zero.When the university rector came to evaluate the work, he said that this might be not the perfect arrangement. He suggested to melt some of the sculptures so that:   the remaining sculptures form a regular polygon (the number of vertices should be between 3 and n),  the sum of the ti values of the remaining sculptures is maximized. Help the Vice Rector to analyze the criticism — find the maximum value of ti sum which can be obtained in this way. It is allowed not to melt any sculptures at all. The sculptures can not be moved.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"308"Let $$$f(i)$$$ denote the minimum positive integer $$$x$$$ such that $$$x$$$ is not a divisor of $$$i$$$.Compute $$$\sum_{i=1}^n f(i)$$$ modulo $$$10^9+7$$$. In other words, compute $$$f(1)+f(2)+\dots+f(n)$$$ modulo $$$10^9+7$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"309"There is a new attraction in Singapore Zoo: The Infinite Zoo.The Infinite Zoo can be represented by a graph with an infinite number of vertices labeled $$$1,2,3,\ldots$$$. There is a directed edge from vertex $$$u$$$ to vertex $$$u+v$$$ if and only if $$$u\&v=v$$$, where $$$\&$$$ denotes the bitwise AND operation. There are no other edges in the graph.Zookeeper has $$$q$$$ queries. In the $$$i$$$-th query she will ask you if she can travel from vertex $$$u_i$$$ to vertex $$$v_i$$$ by going through directed edges.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"310"Sasha and Dima want to buy two $$$n$$$-tier cakes. Each cake should consist of $$$n$$$ different tiers: from the size of $$$1$$$ to the size of $$$n$$$. Tiers should go in order from the smallest to the biggest (from top to bottom).They live on the same street, there are $$$2 \cdot n$$$ houses in a row from left to right. Each house has a pastry shop where you can buy a cake tier. Unfortunately, in each pastry shop you can buy only one tier of only one specific size: in the $$$i$$$-th house you can buy a tier of the size $$$a_i$$$ ($$$1 \le a_i \le n$$$).Since the guys carry already purchased tiers, and it is impossible to insert a new tier in the middle of the cake, they agreed to buy tiers from the smallest to the biggest. That is, each of them buys tiers in order: $$$1$$$, then $$$2$$$, then $$$3$$$ and so on up to $$$n$$$.Initially, Sasha and Dima are located near the first (leftmost) house. Output the minimum distance that they will have to walk in total to buy both cakes. The distance between any two neighboring houses is exactly $$$1$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"311"Vasya has n items lying in a line. The items are consecutively numbered by numbers from 1 to n in such a way that the leftmost item has number 1, the rightmost item has number n. Each item has a weight, the i-th item weights wi kilograms.Vasya needs to collect all these items, however he won't do it by himself. He uses his brand new robot. The robot has two different arms — the left one and the right one. The robot can consecutively perform the following actions:   Take the leftmost item with the left hand and spend wi · l energy units (wi is a weight of the leftmost item, l is some parameter). If the previous action was the same (left-hand), then the robot spends extra Ql energy units;  Take the rightmost item with the right hand and spend wj · r energy units (wj is a weight of the rightmost item, r is some parameter). If the previous action was the same (right-hand), then the robot spends extra Qr energy units; Naturally, Vasya wants to program the robot in a way that the robot spends as little energy as possible. He asked you to solve this problem. Your task is to find the minimum number of energy units robot spends to collect all items.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"312"The 2050 volunteers are organizing the ""Run! Chase the Rising Sun"" activity. Starting on Apr 25 at 7:30 am, runners will complete the 6km trail around the Yunqi town.There are $$$n+1$$$ checkpoints on the trail. They are numbered by $$$0$$$, $$$1$$$, ..., $$$n$$$. A runner must start at checkpoint $$$0$$$ and finish at checkpoint $$$n$$$. No checkpoint is skippable — he must run from checkpoint $$$0$$$ to checkpoint $$$1$$$, then from checkpoint $$$1$$$ to checkpoint $$$2$$$ and so on. Look at the picture in notes section for clarification.Between any two adjacent checkpoints, there are $$$m$$$ different paths to choose. For any $$$1\le i\le n$$$, to run from checkpoint $$$i-1$$$ to checkpoint $$$i$$$, a runner can choose exactly one from the $$$m$$$ possible paths. The length of the $$$j$$$-th path between checkpoint $$$i-1$$$ and $$$i$$$ is $$$b_{i,j}$$$ for any $$$1\le j\le m$$$ and $$$1\le i\le n$$$.To test the trail, we have $$$m$$$ runners. Each runner must run from the checkpoint $$$0$$$ to the checkpoint $$$n$$$ once, visiting all the checkpoints. Every path between every pair of adjacent checkpoints needs to be ran by exactly one runner. If a runner chooses the path of length $$$l_i$$$ between checkpoint $$$i-1$$$ and $$$i$$$ ($$$1\le i\le n$$$), his tiredness is $$$$$$\min_{i=1}^n l_i,$$$$$$ i. e. the minimum length of the paths he takes.Please arrange the paths of the $$$m$$$ runners to minimize the sum of tiredness of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"313"The spring is coming and it means that a lot of fruits appear on the counters. One sunny day little boy Valera decided to go shopping. He made a list of m fruits he wanted to buy. If Valera want to buy more than one fruit of some kind, he includes it into the list several times. When he came to the fruit stall of Ashot, he saw that the seller hadn't distributed price tags to the goods, but put all price tags on the counter. Later Ashot will attach every price tag to some kind of fruits, and Valera will be able to count the total price of all fruits from his list. But Valera wants to know now what can be the smallest total price (in case of the most «lucky» for him distribution of price tags) and the largest total price (in case of the most «unlucky» for him distribution of price tags).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"314"You have a multiset containing several integers. Initially, it contains $$$a_1$$$ elements equal to $$$1$$$, $$$a_2$$$ elements equal to $$$2$$$, ..., $$$a_n$$$ elements equal to $$$n$$$.You may apply two types of operations:  choose two integers $$$l$$$ and $$$r$$$ ($$$l \le r$$$), then remove one occurrence of $$$l$$$, one occurrence of $$$l + 1$$$, ..., one occurrence of $$$r$$$ from the multiset. This operation can be applied only if each number from $$$l$$$ to $$$r$$$ occurs at least once in the multiset;  choose two integers $$$i$$$ and $$$x$$$ ($$$x \ge 1$$$), then remove $$$x$$$ occurrences of $$$i$$$ from the multiset. This operation can be applied only if the multiset contains at least $$$x$$$ occurrences of $$$i$$$. What is the minimum number of operations required to delete all elements from the multiset?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"315"Consider a football tournament where n teams participate. Each team has two football kits: for home games, and for away games. The kit for home games of the i-th team has color xi and the kit for away games of this team has color yi (xi ≠ yi).In the tournament, each team plays exactly one home game and exactly one away game with each other team (n(n - 1) games in total). The team, that plays the home game, traditionally plays in its home kit. The team that plays an away game plays in its away kit. However, if two teams has the kits of the same color, they cannot be distinguished. In this case the away team plays in its home kit.Calculate how many games in the described tournament each team plays in its home kit and how many games it plays in its away kit.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"316"Dmitry has an array of $$$n$$$ non-negative integers $$$a_1, a_2, \dots, a_n$$$.In one operation, Dmitry can choose any index $$$j$$$ ($$$1 \le j \le n$$$) and increase the value of the element $$$a_j$$$ by $$$1$$$. He can choose the same index $$$j$$$ multiple times.For each $$$i$$$ from $$$0$$$ to $$$n$$$, determine whether Dmitry can make the $$$\mathrm{MEX}$$$ of the array equal to exactly $$$i$$$. If it is possible, then determine the minimum number of operations to do it.The $$$\mathrm{MEX}$$$ of the array is equal to the minimum non-negative integer that is not in the array. For example, the $$$\mathrm{MEX}$$$ of the array $$$[3, 1, 0]$$$ is equal to $$$2$$$, and the array $$$[3, 3, 1, 4]$$$ is equal to $$$0$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"317"Ilya plays a card game by the following rules.A player has several cards. Each card contains two non-negative integers inscribed, one at the top of the card and one at the bottom. At the beginning of the round the player chooses one of his cards to play it. If the top of the card contains number ai, and the bottom contains number bi, then when the player is playing the card, he gets ai points and also gets the opportunity to play additional bi cards. After the playing the card is discarded.More formally: let's say that there is a counter of the cards that can be played. At the beginning of the round the counter equals one. When a card is played, the counter decreases by one for the played card and increases by the number bi, which is written at the bottom of the card. Then the played card is discarded. If after that the counter is not equal to zero, the player gets the opportunity to play another card from the remaining cards. The round ends when the counter reaches zero or the player runs out of cards.Of course, Ilya wants to get as many points as possible. Can you determine the maximum number of points he can score provided that you know his cards?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"318"Xenia the mathematician has a sequence consisting of n (n is divisible by 3) positive integers, each of them is at most 7. She wants to split the sequence into groups of three so that for each group of three a, b, c the following conditions held:  a < b < c;  a divides b, b divides c. Naturally, Xenia wants each element of the sequence to belong to exactly one group of three. Thus, if the required partition exists, then it has  groups of three.Help Xenia, find the required partition or else say that it doesn't exist.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"319"You are given string s consists of opening and closing brackets of four kinds <>, {}, [], (). There are two types of brackets: opening and closing. You can replace any bracket by another of the same type. For example, you can replace < by the bracket {, but you can't replace it by ) or >.The following definition of a regular bracket sequence is well-known, so you can be familiar with it.Let's define a regular bracket sequence (RBS). Empty string is RBS. Let s1 and s2 be a RBS then the strings <s1>s2, {s1}s2, [s1]s2, (s1)s2 are also RBS.For example the string ""[[(){}]<>]"" is RBS, but the strings ""[)()"" and ""][()()"" are not.Determine the least number of replaces to make the string s RBS.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"320"You are given $$$n$$$ segments on a number line, numbered from $$$1$$$ to $$$n$$$. The $$$i$$$-th segments covers all integer points from $$$l_i$$$ to $$$r_i$$$ and has a value $$$w_i$$$.You are asked to select a subset of these segments (possibly, all of them). Once the subset is selected, it's possible to travel between two integer points if there exists a selected segment that covers both of them. A subset is good if it's possible to reach point $$$m$$$ starting from point $$$1$$$ in arbitrary number of moves.The cost of the subset is the difference between the maximum and the minimum values of segments in it. Find the minimum cost of a good subset.In every test there exists at least one good subset.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"321"You are given an array $$$a_1, a_2, \dots, a_n$$$. You can perform operations on the array. In each operation you can choose an integer $$$i$$$ ($$$1 \le i < n$$$), and swap elements $$$a_i$$$ and $$$a_{i+1}$$$ of the array, if $$$a_i + a_{i+1}$$$ is odd.Determine whether it can be sorted in non-decreasing order using this operation any number of times.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"322"So, the Berland is at war with its eternal enemy Flatland again, and Vasya, an accountant, was assigned to fulfil his duty to the nation. Right now the situation in Berland is dismal — their both cities are surrounded! The armies of flatlanders stand on the borders of circles, the circles' centers are in the surrounded cities. At any moment all points of the flatland ring can begin to move quickly in the direction of the city — that's the strategy the flatlanders usually follow when they besiege cities.The berlanders are sure that they can repel the enemy's attack if they learn the exact time the attack starts. For that they need to construct a radar that would register any movement at the distance of at most r from it. Thus, we can install a radar at such point, that at least one point of the enemy ring will be in its detecting range (that is, at a distance of at most r). Then the radar can immediately inform about the enemy's attack. Due to the newest technologies, we can place a radar at any point without any problems. But the problem is that the berlanders have the time to make only one radar. Besides, the larger the detection radius (r) is, the more the radar costs.That's why Vasya's task (that is, your task) is to find the minimum possible detection radius for the radar. In other words, your task is to find the minimum radius r (r ≥ 0) such, that a radar with radius r can be installed at some point and it can register the start of the movements of both flatland rings from that point. In this problem you can consider the cities as material points, the attacking enemy rings - as circles with centers in the cities, the radar's detection range — as a disk (including the border) with the center at the point where the radar is placed.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"323"A widely known among some people Belarusian sport programmer Yura possesses lots of information about cars. That is why he has been invited to participate in a game show called ""Guess That Car!"".The game show takes place on a giant parking lot, which is 4n meters long from north to south and 4m meters wide from west to east. The lot has n + 1 dividing lines drawn from west to east and m + 1 dividing lines drawn from north to south, which divide the parking lot into n·m 4 by 4 meter squares. There is a car parked strictly inside each square. The dividing lines are numbered from 0 to n from north to south and from 0 to m from west to east. Each square has coordinates (i, j) so that the square in the north-west corner has coordinates (1, 1) and the square in the south-east corner has coordinates (n, m). See the picture in the notes for clarifications.Before the game show the organizers offer Yura to occupy any of the (n + 1)·(m + 1) intersection points of the dividing lines. After that he can start guessing the cars. After Yura chooses a point, he will be prohibited to move along the parking lot before the end of the game show. As Yura is a car expert, he will always guess all cars he is offered, it's just a matter of time. Yura knows that to guess each car he needs to spend time equal to the square of the euclidean distance between his point and the center of the square with this car, multiplied by some coefficient characterizing the machine's ""rarity"" (the rarer the car is, the harder it is to guess it). More formally, guessing a car with ""rarity"" c placed in a square whose center is at distance d from Yura takes c·d2 seconds. The time Yura spends on turning his head can be neglected.It just so happened that Yura knows the ""rarity"" of each car on the parking lot in advance. Help him choose his point so that the total time of guessing all cars is the smallest possible.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"324"Vanya wants to pass n exams and get the academic scholarship. He will get the scholarship if the average grade mark for all the exams is at least avg. The exam grade cannot exceed r. Vanya has passed the exams and got grade ai for the i-th exam. To increase the grade for the i-th exam by 1 point, Vanya must write bi essays. He can raise the exam grade multiple times.What is the minimum number of essays that Vanya needs to write to get scholarship?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"325"Ramesses knows a lot about problems involving trees (undirected connected graphs without cycles)!He created a new useful tree decomposition, but he does not know how to construct it, so he asked you for help!The decomposition is the splitting the edges of the tree in some simple paths in such a way that each two paths have at least one common vertex. Each edge of the tree should be in exactly one path.Help Remesses, find such a decomposition of the tree or derermine that there is no such decomposition.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"326"You are given an array $$$a$$$ of length $$$n$$$ that consists of zeros and ones.You can perform the following operation multiple times. The operation consists of two steps:   Choose three integers $$$1 \le x < y < z \le n$$$, that form an arithmetic progression ($$$y - x = z - y$$$).  Flip the values $$$a_x, a_y, a_z$$$ (i.e. change $$$1$$$ to $$$0$$$, change $$$0$$$ to $$$1$$$). Determine if it is possible to make all elements of the array equal to zero. If yes, print the operations that lead the the all-zero state. Your solution should not contain more than $$$(\lfloor \frac{n}{3} \rfloor + 12)$$$ operations. Here $$$\lfloor q \rfloor$$$ denotes the number $$$q$$$ rounded down. We can show that it is possible to make all elements equal to zero in no more than this number of operations whenever it is possible to do so at all.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"327"Koa the Koala and her best friend want to play a game.The game starts with an array $$$a$$$ of length $$$n$$$ consisting of non-negative integers. Koa and her best friend move in turns and each have initially a score equal to $$$0$$$. Koa starts.Let's describe a move in the game:  During his move, a player chooses any element of the array and removes it from this array, xor-ing it with the current score of the player. More formally: if the current score of the player is $$$x$$$ and the chosen element is $$$y$$$, his new score will be $$$x \oplus y$$$. Here $$$\oplus$$$ denotes bitwise XOR operation. Note that after a move element $$$y$$$ is removed from $$$a$$$.  The game ends when the array is empty. At the end of the game the winner is the player with the maximum score. If both players have the same score then it's a draw.If both players play optimally find out whether Koa will win, lose or draw the game.","['games', 'math']","[1, 0, 0, 1, 0, 0, 0, 0]"328"Piegirl is buying stickers for a project. Stickers come on sheets, and each sheet of stickers contains exactly n stickers. Each sticker has exactly one character printed on it, so a sheet of stickers can be described by a string of length n. Piegirl wants to create a string s using stickers. She may buy as many sheets of stickers as she wants, and may specify any string of length n for the sheets, but all the sheets must be identical, so the string is the same for all sheets. Once she attains the sheets of stickers, she will take some of the stickers from the sheets and arrange (in any order) them to form s. Determine the minimum number of sheets she has to buy, and provide a string describing a possible sheet of stickers she should buy.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"329"This is an interactive problem.Misha likes to play cooperative games with incomplete information. Today he suggested ten his friends to play a cooperative game ""Lake"".Misha has already come up with a field for the upcoming game. The field for this game is a directed graph consisting of two parts. The first part is a road along the coast of the lake which is a cycle of $$$c$$$ vertices. The second part is a path from home to the lake which is a chain of $$$t$$$ vertices, and there is an edge from the last vertex of this chain to the vertex of the road along the coast which has the most beautiful view of the lake, also known as the finish vertex. Misha decided to keep the field secret, so nobody knows neither $$$t$$$ nor $$$c$$$.  Note that each vertex of the field has exactly one outgoing edge and all the vertices except the home vertex and the finish vertex have exactly one ingoing edge. The home vertex has no incoming edges, the finish vertex has two incoming edges.At the beginning of the game pieces of all the ten players, indexed with consecutive integers from $$$0$$$ to $$$9$$$, are at the home vertex. After that on each turn some of the players can ask Misha to simultaneously move their pieces along the corresponding edges. Misha will not answer more than $$$q$$$ such queries. After each move Misha will tell players whose pieces are at the same vertices and whose pieces are at different vertices.The goal of the game is to move all the pieces to the finish vertex. Misha's friends have no idea how to win in such a game without knowledge of $$$c$$$, $$$t$$$ and $$$q$$$, but luckily they are your friends. Help them: coordinate their actions to win the game. Misha has drawn such a field that $$$1 \le t, c$$$, $$$(t+c) \leq 1000$$$ and $$$q = 3 \cdot (t+c)$$$.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"330"Tonya was given an array of $$$a$$$ of length $$$n$$$ written on a postcard for his birthday. For some reason, the postcard turned out to be a cyclic array, so the index of the element located strictly to the right of the $$$n$$$-th is $$$1$$$. Tonya wanted to study it better, so he bought a robot ""Burenka-179"".A program for Burenka is a pair of numbers $$$(s, k)$$$, where $$$1 \leq s \leq n$$$, $$$1 \leq k \leq n-1$$$. Note that $$$k$$$ cannot be equal to $$$n$$$. Initially, Tonya puts the robot in the position of the array $$$s$$$. After that, Burenka makes exactly $$$n$$$ steps through the array. If at the beginning of a step Burenka stands in the position $$$i$$$, then the following happens:   The number $$$a_{i}$$$ is added to the usefulness of the program.  ""Burenka"" moves $$$k$$$ positions to the right ($$$i := i + k$$$ is executed, if $$$i$$$ becomes greater than $$$n$$$, then $$$i := i - n$$$). Help Tonya find the maximum possible usefulness of a program for ""Burenka"" if the initial usefulness of any program is $$$0$$$.Also, Tony's friend Ilyusha asks him to change the array $$$q$$$ times. Each time he wants to assign $$$a_p := x$$$ for a given index $$$p$$$ and a value $$$x$$$. You need to find the maximum possible usefulness of the program after each of these changes.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"331"Iahub got lost in a very big desert. The desert can be represented as a n × n square matrix, where each cell is a zone of the desert. The cell (i, j) represents the cell at row i and column j (1 ≤ i, j ≤ n). Iahub can go from one cell (i, j) only down or right, that is to cells (i + 1, j) or (i, j + 1). Also, there are m cells that are occupied by volcanoes, which Iahub cannot enter. Iahub is initially at cell (1, 1) and he needs to travel to cell (n, n). Knowing that Iahub needs 1 second to travel from one cell to another, find the minimum time in which he can arrive in cell (n, n).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"332"When little Petya grew up and entered the university, he started to take part in АСМ contests. Later he realized that he doesn't like how the АСМ contests are organised: the team could only have three members (and he couldn't take all his friends to the competitions and distribute the tasks between the team members efficiently), so he decided to organize his own contests PFAST Inc. — Petr and Friends Are Solving Tasks Corporation. PFAST Inc. rules allow a team to have unlimited number of members.To make this format of contests popular he organised his own tournament. To create the team he will prepare for the contest organised by the PFAST Inc. rules, he chose several volunteers (up to 16 people) and decided to compile a team from them. Petya understands perfectly that if a team has two people that don't get on well, then the team will perform poorly. Put together a team with as many players as possible given that all players should get on well with each other.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"333"You are given a rooted tree consisting of $$$n$$$ vertices. Vertices are numbered from $$$1$$$ to $$$n$$$. Any vertex can be the root of a tree.A tree is a connected undirected graph without cycles. A rooted tree is a tree with a selected vertex, which is called the root.The tree is specified by an array of parents $$$p$$$ containing $$$n$$$ numbers: $$$p_i$$$ is a parent of the vertex with the index $$$i$$$. The parent of a vertex $$$u$$$ is a vertex that is the next vertex on the shortest path from $$$u$$$ to the root. For example, on the simple path from $$$5$$$ to $$$3$$$ (the root), the next vertex would be $$$1$$$, so the parent of $$$5$$$ is $$$1$$$.The root has no parent, so for it, the value of $$$p_i$$$ is $$$i$$$ (the root is the only vertex for which $$$p_i=i$$$).Find such a set of paths that:  each vertex belongs to exactly one path, each path can contain one or more vertices;  in each path each next vertex — is a son of the current vertex (that is, paths always lead down — from parent to son);  number of paths is minimal. For example, if $$$n=5$$$ and $$$p=[3, 1, 3, 3, 1]$$$, then the tree can be divided into three paths:   $$$3 \rightarrow 1 \rightarrow 5$$$ (path of $$$3$$$ vertices),  $$$4$$$ (path of $$$1$$$ vertices).  $$$2$$$ (path of $$$1$$$ vertices).     Example of splitting a root tree into three paths for $$$n=5$$$, the root of the tree — node $$$3$$$. ","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"334"Formula One championship consists of series of races called Grand Prix. After every race drivers receive points according to their final position. Only the top 10 drivers receive points in the following order 25, 18, 15, 12, 10, 8, 6, 4, 2, 1. At the conclusion of the championship the driver with most points is the champion. If there is a tie, champion is the one with most wins (i.e. first places). If a tie still exists, it is chosen the one with most second places, and so on, until there are no more place to use for compare. Last year another scoring system was proposed but rejected. In it the champion is the one with most wins. If there is tie, champion is the one with most points. If a tie still exists it is proceeded the same way as in the original scoring system, that is comparing number of second, third, forth, and so on, places.You are given the result of all races during the season and you are to determine the champion according to both scoring systems. It is guaranteed, that both systems will produce unique champion.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"335"You and your friend are participating in a TV show ""Run For Your Prize"".At the start of the show n prizes are located on a straight line. i-th prize is located at position ai. Positions of all prizes are distinct. You start at position 1, your friend — at position 106 (and there is no prize in any of these two positions). You have to work as a team and collect all prizes in minimum possible time, in any order.You know that it takes exactly 1 second to move from position x to position x + 1 or x - 1, both for you and your friend. You also have trained enough to instantly pick up any prize, if its position is equal to your current position (and the same is true for your friend). Carrying prizes does not affect your speed (or your friend's speed) at all.Now you may discuss your strategy with your friend and decide who will pick up each prize. Remember that every prize must be picked up, either by you or by your friend.What is the minimum number of seconds it will take to pick up all the prizes?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"336"The sequence of integers $$$a_1, a_2, \dots, a_k$$$ is called a good array if $$$a_1 = k - 1$$$ and $$$a_1 > 0$$$. For example, the sequences $$$[3, -1, 44, 0], [1, -99]$$$ are good arrays, and the sequences $$$[3, 7, 8], [2, 5, 4, 1], [0]$$$ — are not.A sequence of integers is called good if it can be divided into a positive number of good arrays. Each good array should be a subsegment of sequence and each element of the sequence should belong to exactly one array. For example, the sequences $$$[2, -3, 0, 1, 4]$$$, $$$[1, 2, 3, -3, -9, 4]$$$ are good, and the sequences $$$[2, -3, 0, 1]$$$, $$$[1, 2, 3, -3 -9, 4, 1]$$$ — are not.For a given sequence of numbers, count the number of its subsequences that are good sequences, and print the number of such subsequences modulo 998244353.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"337"You are given a sequence $$$a_1, a_2, \dots, a_n$$$, consisting of integers.You can apply the following operation to this sequence: choose some integer $$$x$$$ and move all elements equal to $$$x$$$ either to the beginning, or to the end of $$$a$$$. Note that you have to move all these elements in one direction in one operation.For example, if $$$a = [2, 1, 3, 1, 1, 3, 2]$$$, you can get the following sequences in one operation (for convenience, denote elements equal to $$$x$$$ as $$$x$$$-elements):   $$$[1, 1, 1, 2, 3, 3, 2]$$$ if you move all $$$1$$$-elements to the beginning;  $$$[2, 3, 3, 2, 1, 1, 1]$$$ if you move all $$$1$$$-elements to the end;  $$$[2, 2, 1, 3, 1, 1, 3]$$$ if you move all $$$2$$$-elements to the beginning;  $$$[1, 3, 1, 1, 3, 2, 2]$$$ if you move all $$$2$$$-elements to the end;  $$$[3, 3, 2, 1, 1, 1, 2]$$$ if you move all $$$3$$$-elements to the beginning;  $$$[2, 1, 1, 1, 2, 3, 3]$$$ if you move all $$$3$$$-elements to the end; You have to determine the minimum number of such operations so that the sequence $$$a$$$ becomes sorted in non-descending order. Non-descending order means that for all $$$i$$$ from $$$2$$$ to $$$n$$$, the condition $$$a_{i-1} \le a_i$$$ is satisfied.Note that you have to answer $$$q$$$ independent queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"338"$$$m$$$ chairs are arranged in a circle sequentially. The chairs are numbered from $$$0$$$ to $$$m-1$$$. $$$n$$$ people want to sit in these chairs. The $$$i$$$-th of them wants at least $$$a[i]$$$ empty chairs both on his right and left side. More formally, if the $$$i$$$-th person sits in the $$$j$$$-th chair, then no one else should sit in the following chairs: $$$(j-a[i]) \bmod m$$$, $$$(j-a[i]+1) \bmod m$$$, ... $$$(j+a[i]-1) \bmod m$$$, $$$(j+a[i]) \bmod m$$$.Decide if it is possible to sit down for all of them, under the given limitations.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"339"You are given two strings $$$s$$$ and $$$t$$$ of equal length $$$n$$$. In one move, you can swap any two adjacent characters of the string $$$s$$$.You need to find the minimal number of operations you need to make string $$$s$$$ lexicographically smaller than string $$$t$$$.A string $$$a$$$ is lexicographically smaller than a string $$$b$$$ if and only if one of the following holds:   $$$a$$$ is a prefix of $$$b$$$, but $$$a \ne b$$$;  in the first position where $$$a$$$ and $$$b$$$ differ, the string $$$a$$$ has a letter that appears earlier in the alphabet than the corresponding letter in $$$b$$$. ",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"340"You are given $$$n$$$ words, each of which consists of lowercase alphabet letters. Each word contains at least one vowel. You are going to choose some of the given words and make as many beautiful lyrics as possible.Each lyric consists of two lines. Each line consists of two words separated by whitespace. A lyric is beautiful if and only if it satisfies all conditions below.   The number of vowels in the first word of the first line is the same as the number of vowels in the first word of the second line.  The number of vowels in the second word of the first line is the same as the number of vowels in the second word of the second line.  The last vowel of the first line is the same as the last vowel of the second line. Note that there may be consonants after the vowel. Also, letters ""a"", ""e"", ""o"", ""i"", and ""u"" are vowels. Note that ""y"" is never vowel.For example of a beautiful lyric,  ""hello hellooowww"" ""whatsup yowowowow""  is a beautiful lyric because there are two vowels each in ""hello"" and ""whatsup"", four vowels each in ""hellooowww"" and ""yowowowow"" (keep in mind that ""y"" is not a vowel), and the last vowel of each line is ""o"".For example of a not beautiful lyric,  ""hey man""""iam mcdic""  is not a beautiful lyric because ""hey"" and ""iam"" don't have same number of vowels and the last vowels of two lines are different (""a"" in the first and ""i"" in the second).How many beautiful lyrics can you write from given words? Note that you cannot use a word more times than it is given to you. For example, if a word is given three times, you can use it at most three times.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"341"Disclaimer: there are lots of untranslateable puns in the Russian version of the statement, so there is one more reason for you to learn Russian :)Rick and Morty like to go to the ridge High Cry for crying loudly — there is an extraordinary echo. Recently they discovered an interesting acoustic characteristic of this ridge: if Rick and Morty begin crying simultaneously from different mountains, their cry would be heard between these mountains up to the height equal the bitwise OR of mountains they've climbed and all the mountains between them. Bitwise OR is a binary operation which is determined the following way. Consider representation of numbers x and y in binary numeric system (probably with leading zeroes) x = xk... x1x0 and y = yk... y1y0. Then z = x | y is defined following way: z = zk... z1z0, where zi = 1, if xi = 1 or yi = 1, and zi = 0 otherwise. In the other words, digit of bitwise OR of two numbers equals zero if and only if digits at corresponding positions is both numbers equals zero. For example bitwise OR of numbers 10 = 10102 and 9 = 10012 equals 11 = 10112. In programming languages C/C++/Java/Python this operation is defined as «|», and in Pascal as «or».Help Rick and Morty calculate the number of ways they can select two mountains in such a way that if they start crying from these mountains their cry will be heard above these mountains and all mountains between them. More formally you should find number of pairs l and r (1 ≤ l < r ≤ n) such that bitwise OR of heights of all mountains between l and r (inclusive) is larger than the height of any mountain at this interval.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"342"Mr. Kitayuta has just bought an undirected graph consisting of n vertices and m edges. The vertices of the graph are numbered from 1 to n. Each edge, namely edge i, has a color ci, connecting vertex ai and bi.Mr. Kitayuta wants you to process the following q queries.In the i-th query, he gives you two integers — ui and vi.Find the number of the colors that satisfy the following condition: the edges of that color connect vertex ui and vertex vi directly or indirectly.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"343"Ray lost his array and needs to find it by asking Omkar. Omkar is willing to disclose that the array has the following qualities:  The array has $$$n$$$ ($$$1 \le n \le 2 \cdot 10^5$$$) elements.  Every element in the array $$$a_i$$$ is an integer in the range $$$1 \le a_i \le 10^9.$$$  The array is sorted in nondecreasing order. Ray is allowed to send Omkar a series of queries. A query consists of two integers, $$$l$$$ and $$$r$$$ such that $$$1 \le l \le r \le n$$$. Omkar will respond with two integers, $$$x$$$ and $$$f$$$. $$$x$$$ is the mode of the subarray from index $$$l$$$ to index $$$r$$$ inclusive. The mode of an array is defined by the number that appears the most frequently. If there are multiple numbers that appear the most number of times, the smallest such number is considered to be the mode. $$$f$$$ is the amount of times that $$$x$$$ appears in the queried subarray.The array has $$$k$$$ ($$$1 \le k \le \min(25000,n)$$$) distinct elements. However, due to Ray's sins, Omkar will not tell Ray what $$$k$$$ is. Ray is allowed to send at most $$$4k$$$ queries.Help Ray find his lost array.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"344"Find out if it is possible to partition the first $$$n$$$ positive integers into two non-empty disjoint sets $$$S_1$$$ and $$$S_2$$$ such that:$$$\mathrm{gcd}(\mathrm{sum}(S_1), \mathrm{sum}(S_2)) > 1$$$ Here $$$\mathrm{sum}(S)$$$ denotes the sum of all elements present in set $$$S$$$ and $$$\mathrm{gcd}$$$ means thegreatest common divisor.Every integer number from $$$1$$$ to $$$n$$$ should be present in exactly one of $$$S_1$$$ or $$$S_2$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"345"There are $$$n$$$ chips arranged in a circle, numbered from $$$1$$$ to $$$n$$$. Initially each chip has black or white color. Then $$$k$$$ iterations occur. During each iteration the chips change their colors according to the following rules. For each chip $$$i$$$, three chips are considered: chip $$$i$$$ itself and two its neighbours. If the number of white chips among these three is greater than the number of black chips among these three chips, then the chip $$$i$$$ becomes white. Otherwise, the chip $$$i$$$ becomes black. Note that for each $$$i$$$ from $$$2$$$ to $$$(n - 1)$$$ two neighbouring chips have numbers $$$(i - 1)$$$ and $$$(i + 1)$$$. The neighbours for the chip $$$i = 1$$$ are $$$n$$$ and $$$2$$$. The neighbours of $$$i = n$$$ are $$$(n - 1)$$$ and $$$1$$$.The following picture describes one iteration with $$$n = 6$$$. The chips $$$1$$$, $$$3$$$ and $$$4$$$ are initially black, and the chips $$$2$$$, $$$5$$$ and $$$6$$$ are white. After the iteration $$$2$$$, $$$3$$$ and $$$4$$$ become black, and $$$1$$$, $$$5$$$ and $$$6$$$ become white.  Your task is to determine the color of each chip after $$$k$$$ iterations.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"346"Bees Alice and Alesya gave beekeeper Polina famous card game ""Set"" as a Christmas present. The deck consists of cards that vary in four features across three options for each kind of feature: number of shapes, shape, shading, and color. In this game, some combinations of three cards are said to make up a set. For every feature — color, number, shape, and shading — the three cards must display that feature as either all the same, or pairwise different. The picture below shows how sets look.Polina came up with a new game called ""Hyperset"". In her game, there are $$$n$$$ cards with $$$k$$$ features, each feature has three possible values: ""S"", ""E"", or ""T"". The original ""Set"" game can be viewed as ""Hyperset"" with $$$k = 4$$$.Similarly to the original game, three cards form a set, if all features are the same for all cards or are pairwise different. The goal of the game is to compute the number of ways to choose three cards that form a set.Unfortunately, winter holidays have come to an end, and it's time for Polina to go to school. Help Polina find the number of sets among the cards lying on the table.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"347"Roma works in a company that sells TVs. Now he has to prepare a report for the last year.Roma has got a list of the company's incomes. The list is a sequence that consists of n integers. The total income of the company is the sum of all integers in sequence. Roma decided to perform exactly k changes of signs of several numbers in the sequence. He can also change the sign of a number one, two or more times.The operation of changing a number's sign is the operation of multiplying this number by -1.Help Roma perform the changes so as to make the total income of the company (the sum of numbers in the resulting sequence) maximum. Note that Roma should perform exactly k changes.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"348"Roy and Biv have a set of n points on the infinite number line.Each point has one of 3 colors: red, green, or blue.Roy and Biv would like to connect all the points with some edges. Edges can be drawn between any of the two of the given points. The cost of an edge is equal to the distance between the two points it connects.They want to do this in such a way that they will both see that all the points are connected (either directly or indirectly).However, there is a catch: Roy cannot see the color red and Biv cannot see the color blue.Therefore, they have to choose the edges in such a way that if all the red points are removed, the remaining blue and green points are connected (and similarly, if all the blue points are removed, the remaining red and green points are connected).Help them compute the minimum cost way to choose edges to satisfy the above constraints.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"349"Vasya has got $$$n$$$ books, numbered from $$$1$$$ to $$$n$$$, arranged in a stack. The topmost book has number $$$a_1$$$, the next one — $$$a_2$$$, and so on. The book at the bottom of the stack has number $$$a_n$$$. All numbers are distinct.Vasya wants to move all the books to his backpack in $$$n$$$ steps. During $$$i$$$-th step he wants to move the book number $$$b_i$$$ into his backpack. If the book with number $$$b_i$$$ is in the stack, he takes this book and all the books above the book $$$b_i$$$, and puts them into the backpack; otherwise he does nothing and begins the next step. For example, if books are arranged in the order $$$[1, 2, 3]$$$ (book $$$1$$$ is the topmost), and Vasya moves the books in the order $$$[2, 1, 3]$$$, then during the first step he will move two books ($$$1$$$ and $$$2$$$), during the second step he will do nothing (since book $$$1$$$ is already in the backpack), and during the third step — one book (the book number $$$3$$$). Note that $$$b_1, b_2, \dots, b_n$$$ are distinct.Help Vasya! Tell him the number of books he will put into his backpack during each step.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"350"This is a simplified version of the problem B2. Perhaps you should read the problem B2 before you start solving B1.Paul and Mary have a favorite string $$$s$$$ which consists of lowercase letters of the Latin alphabet. They want to paint it using pieces of chalk of two colors: red and green. Let's call a coloring of a string wonderful if the following conditions are met:  each letter of the string is either painted in exactly one color (red or green) or isn't painted;  each two letters which are painted in the same color are different;  the number of letters painted in red is equal to the number of letters painted in green;  the number of painted letters of this coloring is maximum among all colorings of the string which meet the first three conditions. E. g. consider a string $$$s$$$ equal to ""kzaaa"". One of the wonderful colorings of the string is shown in the figure.    The example of a wonderful coloring of the string ""kzaaa"". Paul and Mary want to learn by themselves how to find a wonderful coloring of the string. But they are very young, so they need a hint. Help them find $$$k$$$ — the number of red (or green, these numbers are equal) letters in a wonderful coloring.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"351"Vasya goes to visit his classmate Petya. Vasya knows that Petya's apartment number is $$$n$$$. There is only one entrance in Petya's house and the distribution of apartments is the following: the first floor contains $$$2$$$ apartments, every other floor contains $$$x$$$ apartments each. Apartments are numbered starting from one, from the first floor. I.e. apartments on the first floor have numbers $$$1$$$ and $$$2$$$, apartments on the second floor have numbers from $$$3$$$ to $$$(x + 2)$$$, apartments on the third floor have numbers from $$$(x + 3)$$$ to $$$(2 \cdot x + 2)$$$, and so on.Your task is to find the number of floor on which Petya lives. Assume that the house is always high enough to fit at least $$$n$$$ apartments.You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"352"Old timers of Summer Informatics School can remember previous camps in which each student was given a drink of his choice on the vechorka (late-evening meal). Or may be the story was more complicated?There are $$$n$$$ students living in a building, and for each of them the favorite drink $$$a_i$$$ is known. So you know $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$, where $$$a_i$$$ ($$$1 \le a_i \le k$$$) is the type of the favorite drink of the $$$i$$$-th student. The drink types are numbered from $$$1$$$ to $$$k$$$.There are infinite number of drink sets. Each set consists of exactly two portions of the same drink. In other words, there are $$$k$$$ types of drink sets, the $$$j$$$-th type contains two portions of the drink $$$j$$$. The available number of sets of each of the $$$k$$$ types is infinite.You know that students will receive the minimum possible number of sets to give all students exactly one drink. Obviously, the number of sets will be exactly $$$\lceil \frac{n}{2} \rceil$$$, where $$$\lceil x \rceil$$$ is $$$x$$$ rounded up.After students receive the sets, they will distribute their portions by their choice: each student will get exactly one portion. Note, that if $$$n$$$ is odd then one portion will remain unused and the students' teacher will drink it.What is the maximum number of students that can get their favorite drink if $$$\lceil \frac{n}{2} \rceil$$$ sets will be chosen optimally and students will distribute portions between themselves optimally?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"353"Wu got hungry after an intense training session, and came to a nearby store to buy his favourite instant noodles. After Wu paid for his purchase, the cashier gave him an interesting task.You are given a bipartite graph with positive integers in all vertices of the right half. For a subset $$$S$$$ of vertices of the left half we define $$$N(S)$$$ as the set of all vertices of the right half adjacent to at least one vertex in $$$S$$$, and $$$f(S)$$$ as the sum of all numbers in vertices of $$$N(S)$$$. Find the greatest common divisor of $$$f(S)$$$ for all possible non-empty subsets $$$S$$$ (assume that GCD of empty set is $$$0$$$).Wu is too tired after his training to solve this problem. Help him!","['graphs', 'math', 'number theory']","[0, 0, 1, 1, 1, 0, 0, 0]"354"You are given a permutation $$$p_1, p_2, \dots , p_n$$$ (an array where each integer from $$$1$$$ to $$$n$$$ appears exactly once). The weight of the $$$i$$$-th element of this permutation is $$$a_i$$$.At first, you separate your permutation into two non-empty sets — prefix and suffix. More formally, the first set contains elements $$$p_1, p_2, \dots , p_k$$$, the second — $$$p_{k+1}, p_{k+2}, \dots , p_n$$$, where $$$1 \le k < n$$$.After that, you may move elements between sets. The operation you are allowed to do is to choose some element of the first set and move it to the second set, or vice versa (move from the second set to the first). You have to pay $$$a_i$$$ dollars to move the element $$$p_i$$$.Your goal is to make it so that each element of the first set is less than each element of the second set. Note that if one of the sets is empty, this condition is met.For example, if $$$p = [3, 1, 2]$$$ and $$$a = [7, 1, 4]$$$, then the optimal strategy is: separate $$$p$$$ into two parts $$$[3, 1]$$$ and $$$[2]$$$ and then move the $$$2$$$-element into first set (it costs $$$4$$$). And if $$$p = [3, 5, 1, 6, 2, 4]$$$, $$$a = [9, 1, 9, 9, 1, 9]$$$, then the optimal strategy is: separate $$$p$$$ into two parts $$$[3, 5, 1]$$$ and $$$[6, 2, 4]$$$, and then move the $$$2$$$-element into first set (it costs $$$1$$$), and $$$5$$$-element into second set (it also costs $$$1$$$).Calculate the minimum number of dollars you have to spend.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"355" If the girl doesn't go to Denis, then Denis will go to the girl. Using this rule, the young man left home, bought flowers and went to Nastya. On the way from Denis's house to the girl's house is a road of $$$n$$$ lines. This road can't be always crossed in one green light. Foreseeing this, the good mayor decided to place safety islands in some parts of the road. Each safety island is located after a line, as well as at the beginning and at the end of the road. Pedestrians can relax on them, gain strength and wait for a green light.Denis came to the edge of the road exactly at the moment when the green light turned on. The boy knows that the traffic light first lights up $$$g$$$ seconds green, and then $$$r$$$ seconds red, then again $$$g$$$ seconds green and so on.Formally, the road can be represented as a segment $$$[0, n]$$$. Initially, Denis is at point $$$0$$$. His task is to get to point $$$n$$$ in the shortest possible time.He knows many different integers $$$d_1, d_2, \ldots, d_m$$$, where $$$0 \leq d_i \leq n$$$  — are the coordinates of points, in which the safety islands are located. Only at one of these points, the boy can be at a time when the red light is on.Unfortunately, Denis isn't always able to control himself because of the excitement, so some restrictions are imposed:  He must always move while the green light is on because it's difficult to stand when so beautiful girl is waiting for you. Denis can change his position by $$$\pm 1$$$ in $$$1$$$ second. While doing so, he must always stay inside the segment $$$[0, n]$$$.  He can change his direction only on the safety islands (because it is safe). This means that if in the previous second the boy changed his position by $$$+1$$$ and he walked on a safety island, then he can change his position by $$$\pm 1$$$. Otherwise, he can change his position only by $$$+1$$$. Similarly, if in the previous second he changed his position by $$$-1$$$, on a safety island he can change position by $$$\pm 1$$$, and at any other point by $$$-1$$$.  At the moment when the red light is on, the boy must be on one of the safety islands. He can continue moving in any direction when the green light is on. Denis has crossed the road as soon as his coordinate becomes equal to $$$n$$$.This task was not so simple, because it's possible that it is impossible to cross the road. Since Denis has all thoughts about his love, he couldn't solve this problem and asked us to help him. Find the minimal possible time for which he can cross the road according to these rules, or find that it is impossible to do.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"356"You are given a string $$$s$$$ consisting of the characters 0, 1, and ?.Let's call a string unstable if it consists of the characters 0 and 1 and any two adjacent characters are different (i. e. it has the form 010101... or 101010...).Let's call a string beautiful if it consists of the characters 0, 1, and ?, and you can replace the characters ? to 0 or 1 (for each character, the choice is independent), so that the string becomes unstable.For example, the strings 0??10, 0, and ??? are beautiful, and the strings 00 and ?1??1 are not.Calculate the number of beautiful contiguous substrings of the string $$$s$$$.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"357"There are $$$n$$$ dormitories in Berland State University, they are numbered with integers from $$$1$$$ to $$$n$$$. Each dormitory consists of rooms, there are $$$a_i$$$ rooms in $$$i$$$-th dormitory. The rooms in $$$i$$$-th dormitory are numbered from $$$1$$$ to $$$a_i$$$.A postman delivers letters. Sometimes there is no specific dormitory and room number in it on an envelope. Instead of it only a room number among all rooms of all $$$n$$$ dormitories is written on an envelope. In this case, assume that all the rooms are numbered from $$$1$$$ to $$$a_1 + a_2 + \dots + a_n$$$ and the rooms of the first dormitory go first, the rooms of the second dormitory go after them and so on.For example, in case $$$n=2$$$, $$$a_1=3$$$ and $$$a_2=5$$$ an envelope can have any integer from $$$1$$$ to $$$8$$$ written on it. If the number $$$7$$$ is written on an envelope, it means that the letter should be delivered to the room number $$$4$$$ of the second dormitory.For each of $$$m$$$ letters by the room number among all $$$n$$$ dormitories, determine the particular dormitory and the room number in a dormitory where this letter should be delivered.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"358"The life goes up and down, just like nice sequences. Sequence t1, t2, ..., tn is called nice if the following two conditions are satisfied:   ti < ti + 1 for each odd i < n;  ti > ti + 1 for each even i < n. For example, sequences (2, 8), (1, 5, 1) and (2, 5, 1, 100, 99, 120) are nice, while (1, 1), (1, 2, 3) and (2, 5, 3, 2) are not.Bear Limak has a sequence of positive integers t1, t2, ..., tn. This sequence is not nice now and Limak wants to fix it by a single swap. He is going to choose two indices i < j and swap elements ti and tj in order to get a nice sequence. Count the number of ways to do so. Two ways are considered different if indices of elements chosen for a swap are different.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"359"For each string s consisting of characters '0' and '1' one can define four integers a00, a01, a10 and a11, where axy is the number of subsequences of length 2 of the string s equal to the sequence {x, y}. In these problem you are given four integers a00, a01, a10, a11 and have to find any non-empty string s that matches them, or determine that there is no such string. One can prove that if at least one answer exists, there exists an answer of length no more than 1 000 000.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"360"You are given two positive integers $$$n$$$ and $$$s$$$. Find the maximum possible median of an array of $$$n$$$ non-negative integers (not necessarily distinct), such that the sum of its elements is equal to $$$s$$$.A median of an array of integers of length $$$m$$$ is the number standing on the $$$\lceil {\frac{m}{2}} \rceil$$$-th (rounding up) position in the non-decreasing ordering of its elements. Positions are numbered starting from $$$1$$$. For example, a median of the array $$$[20,40,20,50,50,30]$$$ is the $$$\lceil \frac{m}{2} \rceil$$$-th element of $$$[20,20,30,40,50,50]$$$, so it is $$$30$$$. There exist other definitions of the median, but in this problem we use the described definition.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"361"Artsem has a friend Saunders from University of Chicago. Saunders presented him with the following problem.Let [n] denote the set {1, ..., n}. We will also write f: [x] → [y] when a function f is defined in integer points 1, ..., x, and all its values are integers from 1 to y.Now then, you are given a function f: [n] → [n]. Your task is to find a positive integer m, and two functions g: [n] → [m], h: [m] → [n], such that g(h(x)) = x for all , and h(g(x)) = f(x) for all , or determine that finding these is impossible.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"362"Petya once wrote a sad love song and shared it to Vasya. The song is a string consisting of lowercase English letters. Vasya made up $$$q$$$ questions about this song. Each question is about a subsegment of the song starting from the $$$l$$$-th letter to the $$$r$$$-th letter. Vasya considers a substring made up from characters on this segment and repeats each letter in the subsegment $$$k$$$ times, where $$$k$$$ is the index of the corresponding letter in the alphabet. For example, if the question is about the substring ""abbcb"", then Vasya repeats letter 'a' once, each of the letters 'b' twice, letter 'c"" three times, so that the resulting string is ""abbbbcccbb"", its length is $$$10$$$. Vasya is interested about the length of the resulting string.Help Petya find the length of each string obtained by Vasya.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"363"Let's call an array $$$t$$$ dominated by value $$$v$$$ in the next situation.At first, array $$$t$$$ should have at least $$$2$$$ elements. Now, let's calculate number of occurrences of each number $$$num$$$ in $$$t$$$ and define it as $$$occ(num)$$$. Then $$$t$$$ is dominated (by $$$v$$$) if (and only if) $$$occ(v) > occ(v')$$$ for any other number $$$v'$$$. For example, arrays $$$[1, 2, 3, 4, 5, 2]$$$, $$$[11, 11]$$$ and $$$[3, 2, 3, 2, 3]$$$ are dominated (by $$$2$$$, $$$11$$$ and $$$3$$$ respectevitely) but arrays $$$[3]$$$, $$$[1, 2]$$$ and $$$[3, 3, 2, 2, 1]$$$ are not.Small remark: since any array can be dominated only by one number, we can not specify this number and just say that array is either dominated or not.You are given array $$$a_1, a_2, \dots, a_n$$$. Calculate its shortest dominated subarray or say that there are no such subarrays.The subarray of $$$a$$$ is a contiguous part of the array $$$a$$$, i. e. the array $$$a_i, a_{i + 1}, \dots, a_j$$$ for some $$$1 \le i \le j \le n$$$.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"364"Woken up by the alarm clock Igor the financial analyst hurried up to the work. He ate his breakfast and sat in his car. Sadly, when he opened his GPS navigator, he found that some of the roads in Bankopolis, the city where he lives, are closed due to road works. Moreover, Igor has some problems with the steering wheel, so he can make no more than two turns on his way to his office in bank.Bankopolis looks like a grid of n rows and m columns. Igor should find a way from his home to the bank that has no more than two turns and doesn't contain cells with road works, or determine that it is impossible and he should work from home. A turn is a change in movement direction. Igor's car can only move to the left, to the right, upwards and downwards. Initially Igor can choose any direction. Igor is still sleepy, so you should help him.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"365"Arkady owns a non-decreasing array $$$a_1, a_2, \ldots, a_n$$$. You are jealous of its beauty and want to destroy this property. You have a so-called XOR-gun that you can use one or more times.In one step you can select two consecutive elements of the array, let's say $$$x$$$ and $$$y$$$, remove them from the array and insert the integer $$$x \oplus y$$$ on their place, where $$$\oplus$$$ denotes the bitwise XOR operation. Note that the length of the array decreases by one after the operation. You can't perform this operation when the length of the array reaches one.For example, if the array is $$$[2, 5, 6, 8]$$$, you can select $$$5$$$ and $$$6$$$ and replace them with $$$5 \oplus 6 = 3$$$. The array becomes $$$[2, 3, 8]$$$.You want the array no longer be non-decreasing. What is the minimum number of steps needed? If the array stays non-decreasing no matter what you do, print $$$-1$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"366"Polycarp invented a new way to encode strings. Let's assume that we have string T, consisting of lowercase English letters. Let's choose several pairs of letters of the English alphabet in such a way that each letter occurs in at most one pair. Then let's replace each letter in T with its pair letter if there is a pair letter for it. For example, if you chose pairs (l, r), (p, q) and (a, o), then word ""parallelogram"" according to the given encoding principle transforms to word ""qolorreraglom"".Polycarpus already has two strings, S and T. He suspects that string T was obtained after applying the given encoding method from some substring of string S. Find all positions mi in S (1 ≤ mi ≤ |S| - |T| + 1), such that T can be obtained fro substring SmiSmi + 1... Smi + |T| - 1 by applying the described encoding operation by using some set of pairs of English alphabet letters",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"367"Theofanis started playing the new online game called ""Among them"". However, he always plays with Cypriot players, and they all have the same name: ""Andreas"" (the most common name in Cyprus).In each game, Theofanis plays with $$$n$$$ other players. Since they all have the same name, they are numbered from $$$1$$$ to $$$n$$$.The players write $$$m$$$ comments in the chat. A comment has the structure of ""$$$i$$$ $$$j$$$ $$$c$$$"" where $$$i$$$ and $$$j$$$ are two distinct integers and $$$c$$$ is a string ($$$1 \le i, j \le n$$$; $$$i \neq j$$$; $$$c$$$ is either imposter or crewmate). The comment means that player $$$i$$$ said that player $$$j$$$ has the role $$$c$$$.An imposter always lies, and a crewmate always tells the truth. Help Theofanis find the maximum possible number of imposters among all the other Cypriot players, or determine that the comments contradict each other (see the notes for further explanation).Note that each player has exactly one role: either imposter or crewmate.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"368"Vasya has $$$n$$$ different points $$$A_1, A_2, \ldots A_n$$$ on the plane. No three of them lie on the same line He wants to place them in some order $$$A_{p_1}, A_{p_2}, \ldots, A_{p_n}$$$, where $$$p_1, p_2, \ldots, p_n$$$ — some permutation of integers from $$$1$$$ to $$$n$$$.After doing so, he will draw oriented polygonal line on these points, drawing oriented segments from each point to the next in the chosen order. So, for all $$$1 \leq i \leq n-1$$$ he will draw oriented segment from point $$$A_{p_i}$$$ to point $$$A_{p_{i+1}}$$$. He wants to make this polygonal line satisfying $$$2$$$ conditions:   it will be non-self-intersecting, so any $$$2$$$ segments which are not neighbors don't have common points.  it will be winding. Vasya has a string $$$s$$$, consisting of $$$(n-2)$$$ symbols ""L"" or ""R"". Let's call an oriented polygonal line winding, if its $$$i$$$-th turn left, if $$$s_i = $$$ ""L"" and right, if $$$s_i = $$$ ""R"". More formally: $$$i$$$-th turn will be in point $$$A_{p_{i+1}}$$$, where oriented segment from point $$$A_{p_i}$$$ to point $$$A_{p_{i+1}}$$$ changes to oriented segment from point $$$A_{p_{i+1}}$$$ to point $$$A_{p_{i+2}}$$$. Let's define vectors $$$\overrightarrow{v_1} = \overrightarrow{A_{p_i} A_{p_{i+1}}}$$$ and $$$\overrightarrow{v_2} = \overrightarrow{A_{p_{i+1}} A_{p_{i+2}}}$$$. Then if in order to rotate the vector $$$\overrightarrow{v_1}$$$ by the smallest possible angle, so that its direction coincides with the direction of the vector $$$\overrightarrow{v_2}$$$ we need to make a turn counterclockwise, then we say that $$$i$$$-th turn is to the left, and otherwise to the right. For better understanding look at this pictures with some examples of turns:    There are left turns on this picture     There are right turns on this picture You are given coordinates of the points $$$A_1, A_2, \ldots A_n$$$ on the plane and string $$$s$$$. Find a permutation $$$p_1, p_2, \ldots, p_n$$$ of the integers from $$$1$$$ to $$$n$$$, such that the polygonal line, drawn by Vasya satisfy two necessary conditions.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"369"There are three cells on an infinite 2-dimensional grid, labeled $$$A$$$, $$$B$$$, and $$$F$$$. Find the length of the shortest path from $$$A$$$ to $$$B$$$ if:   in one move you can go to any of the four adjacent cells sharing a side;  visiting the cell $$$F$$$ is forbidden (it is an obstacle). ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"370"This problem is interactive.We decided to play a game with you and guess the number $$$x$$$ ($$$1 \le x < n$$$), where you know the number $$$n$$$.You can make queries like this: + c: this command assigns $$$x = x + c$$$ ($$$1 \le c < n$$$) and then returns you the value $$$\lfloor\frac{x}{n}\rfloor$$$ ($$$x$$$ divide by $$$n$$$ and round down).You win if you guess the current number with no more than $$$10$$$ queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"371"You are given two arrays $$$a$$$ and $$$b$$$, both of length $$$n$$$.You can perform the following operation any number of times (possibly zero): select an index $$$i$$$ ($$$1 \leq i \leq n$$$) and swap $$$a_i$$$ and $$$b_i$$$.Let's define the cost of the array $$$a$$$ as $$$\sum_{i=1}^{n} \sum_{j=i + 1}^{n} (a_i + a_j)^2$$$. Similarly, the cost of the array $$$b$$$ is $$$\sum_{i=1}^{n} \sum_{j=i + 1}^{n} (b_i + b_j)^2$$$.Your task is to minimize the total cost of two arrays.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"372"This is an interactive problem. In the output section below you will see the information about flushing the output.Bear Limak thinks of some hidden number — an integer from interval [2, 100]. Your task is to say if the hidden number is prime or composite.Integer x > 1 is called prime if it has exactly two distinct divisors, 1 and x. If integer x > 1 is not prime, it's called composite.You can ask up to 20 queries about divisors of the hidden number. In each query you should print an integer from interval [2, 100]. The system will answer ""yes"" if your integer is a divisor of the hidden number. Otherwise, the answer will be ""no"".For example, if the hidden number is 14 then the system will answer ""yes"" only if you print 2, 7 or 14.When you are done asking queries, print ""prime"" or ""composite"" and terminate your program.You will get the Wrong Answer verdict if you ask more than 20 queries, or if you print an integer not from the range [2, 100]. Also, you will get the Wrong Answer verdict if the printed answer isn't correct.You will get the Idleness Limit Exceeded verdict if you don't print anything (but you should) or if you forget about flushing the output (more info below).",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"373"Jamie has recently found undirected weighted graphs with the following properties very interesting:  The graph is connected and contains exactly n vertices and m edges.  All edge weights are integers and are in range [1, 109] inclusive.  The length of shortest path from 1 to n is a prime number.  The sum of edges' weights in the minimum spanning tree (MST) of the graph is a prime number.  The graph contains no loops or multi-edges. If you are not familiar with some terms from the statement you can find definitions of them in notes section. Help Jamie construct any graph with given number of vertices and edges that is interesting!",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"374"Alice likes snow a lot! Unfortunately, this year's winter is already over, and she can't expect to have any more of it. Bob has thus bought her a gift — a large snow maker. He plans to make some amount of snow every day. On day i he will make a pile of snow of volume Vi and put it in her garden.Each day, every pile will shrink a little due to melting. More precisely, when the temperature on a given day is Ti, each pile will reduce its volume by Ti. If this would reduce the volume of a pile to or below zero, it disappears forever. All snow piles are independent of each other. Note that the pile made on day i already loses part of its volume on the same day. In an extreme case, this may mean that there are no piles left at the end of a particular day.You are given the initial pile sizes and the temperature on each day. Determine the total volume of snow melted on each day. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"375"A way to make a new task is to make it nondeterministic or probabilistic. For example, the hard task of Topcoder SRM 595, Constellation, is the probabilistic version of a convex hull.Let's try to make a new task. Firstly we will use the following task. There are n people, sort them by their name. It is just an ordinary sorting problem, but we can make it more interesting by adding nondeterministic element. There are n people, each person will use either his/her first name or last name as a handle. Can the lexicographical order of the handles be exactly equal to the given permutation p?More formally, if we denote the handle of the i-th person as hi, then the following condition must hold: .",[],"[0, 0, 0, 0, 0, 0, 0, 0]"376"You are given a positive integer $$$n$$$. Since $$$n$$$ may be very large, you are given its binary representation.You should compute the number of triples $$$(a,b,c)$$$ with $$$0 \leq a,b,c \leq n$$$ such that $$$a \oplus b$$$, $$$b \oplus c$$$, and $$$a \oplus c$$$ are the sides of a non-degenerate triangle. Here, $$$\oplus$$$ denotes the bitwise XOR operation.You should output the answer modulo $$$998\,244\,353$$$.Three positive values $$$x$$$, $$$y$$$, and $$$z$$$ are the sides of a non-degenerate triangle if and only if $$$x+y>z$$$, $$$x+z>y$$$, and $$$y+z>x$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"377"There are $$$n$$$ people in a row. The height of the $$$i$$$-th person is $$$a_i$$$. You can choose any subset of these people and try to arrange them into a balanced circle.A balanced circle is such an order of people that the difference between heights of any adjacent people is no more than $$$1$$$. For example, let heights of chosen people be $$$[a_{i_1}, a_{i_2}, \dots, a_{i_k}]$$$, where $$$k$$$ is the number of people you choose. Then the condition $$$|a_{i_j} - a_{i_{j + 1}}| \le 1$$$ should be satisfied for all $$$j$$$ from $$$1$$$ to $$$k-1$$$ and the condition $$$|a_{i_1} - a_{i_k}| \le 1$$$ should be also satisfied. $$$|x|$$$ means the absolute value of $$$x$$$. It is obvious that the circle consisting of one person is balanced.Your task is to choose the maximum number of people and construct a balanced circle consisting of all chosen people. It is obvious that the circle consisting of one person is balanced so the answer always exists.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"378"Kolya has a string s of length n consisting of lowercase and uppercase Latin letters and digits.He wants to rearrange the symbols in s and cut it into the minimum number of parts so that each part is a palindrome and all parts have the same lengths. A palindrome is a string which reads the same backward as forward, such as madam or racecar.Your task is to help Kolya and determine the minimum number of palindromes of equal lengths to cut s into, if it is allowed to rearrange letters in s before cuttings.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"379"You are running through a rectangular field. This field can be represented as a matrix with 3 rows and m columns. (i, j) denotes a cell belonging to i-th row and j-th column.You start in (2, 1) and have to end your path in (2, m). From the cell (i, j) you may advance to:  (i - 1, j + 1) — only if i > 1,  (i, j + 1), or  (i + 1, j + 1) — only if i < 3. However, there are n obstacles blocking your path. k-th obstacle is denoted by three integers ak, lk and rk, and it forbids entering any cell (ak, j) such that lk ≤ j ≤ rk.You have to calculate the number of different paths from (2, 1) to (2, m), and print it modulo 109 + 7.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"380"There are some tasks which have the following structure: you are given a model, and you can do some operations, you should use these operations to achive the goal. One way to create a new task is to use the same model and same operations, but change the goal.Let's have a try. I have created the following task for Topcoder SRM 557 Div1-Hard: you are given n integers x1, x2, ..., xn. You are allowed to perform the assignments (as many as you want) of the following form xi ^= xj (in the original task i and j must be different, but in this task we allow i to equal j). The goal is to maximize the sum of all xi.Now we just change the goal. You are also given n integers y1, y2, ..., yn. You should make x1, x2, ..., xn exactly equal to y1, y2, ..., yn. In other words, for each i number xi should be equal to yi.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"381"You are given two strings a and b. You have to remove the minimum possible number of consecutive (standing one after another) characters from string b in such a way that it becomes a subsequence of string a. It can happen that you will not need to remove any characters at all, or maybe you will have to remove all of the characters from b and make it empty.Subsequence of string s is any such string that can be obtained by erasing zero or more characters (not necessarily consecutive) from string s.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"382"Mocha wants to be an astrologer. There are $$$n$$$ stars which can be seen in Zhijiang, and the brightness of the $$$i$$$-th star is $$$a_i$$$. Mocha considers that these $$$n$$$ stars form a constellation, and she uses $$$(a_1,a_2,\ldots,a_n)$$$ to show its state. A state is called mathematical if all of the following three conditions are satisfied:  For all $$$i$$$ ($$$1\le i\le n$$$), $$$a_i$$$ is an integer in the range $$$[l_i, r_i]$$$. $$$\sum \limits _{i=1} ^ n a_i \le m$$$. $$$\gcd(a_1,a_2,\ldots,a_n)=1$$$. Here, $$$\gcd(a_1,a_2,\ldots,a_n)$$$ denotes the greatest common divisor (GCD) of integers $$$a_1,a_2,\ldots,a_n$$$.Mocha is wondering how many different mathematical states of this constellation exist. Because the answer may be large, you must find it modulo $$$998\,244\,353$$$.Two states $$$(a_1,a_2,\ldots,a_n)$$$ and $$$(b_1,b_2,\ldots,b_n)$$$ are considered different if there exists $$$i$$$ ($$$1\le i\le n$$$) such that $$$a_i \ne b_i$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"383"The Human-Cow Confederation (HC2), led by Heidi, has built a base where people and cows can hide, guarded from zombie attacks. The entrance to the base is protected by an automated gate which performs a kind of a Turing test: it shows the entering creature a photograph and asks them whether the top and bottom halves of this photograph have been swapped or not. A person (or even a cow) will have no problem answering such questions; on the other hand, a zombie would just randomly smash one of the two buttons.The creature is asked a series of such questions. If at least 75% of them are answered correctly, the gate is unlocked; otherwise, a side door opens, beneath which a huge fan is spinning...Heidi is now building a robot army to fight the zombies, and she wants the robots to also be able to enter the base. You are tasked with programming them to distinguish the images. The first two images from the test set. The first picture has been rearranged, but not the second. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"384"Tyndex is again well ahead of the rivals! The reaction to the release of Zoozle Chrome browser was the release of a new browser Tyndex.Brome!The popularity of the new browser is growing daily. And the secret is not even the Tyndex.Bar installed (the Tyndex.Bar automatically fills the glass with the finest 1664 cognac after you buy Tyndex.Bottles and insert in into a USB port). It is highly popular due to the well-thought interaction with the user.Let us take, for example, the system of automatic address correction. Have you entered codehorses instead of codeforces? The gloomy Zoozle Chrome will sadly say that the address does not exist. Tyndex.Brome at the same time will automatically find the closest address and sent you there. That's brilliant!How does this splendid function work? That's simple! For each potential address a function of the F error is calculated by the following rules:  for every letter ci from the potential address c the closest position j of the letter ci in the address (s) entered by the user is found. The absolute difference |i - j| of these positions is added to F. So for every i (1 ≤ i ≤ |c|) the position j is chosen such, that ci = sj, and |i - j| is minimal possible.  if no such letter ci exists in the address entered by the user, then the length of the potential address |c| is added to F. After the values of the error function have been calculated for all the potential addresses the most suitable one is found. To understand the special features of the above described method better, it is recommended to realize the algorithm of calculating the F function for an address given by the user and some set of potential addresses. Good luck!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"385"A binary string is a string consisting only of the characters 0 and 1. You are given a binary string $$$s_1 s_2 \ldots s_n$$$. It is necessary to make this string non-decreasing in the least number of operations. In other words, each character should be not less than the previous. In one operation, you can do the following: Select an arbitrary index $$$1 \leq i \leq n$$$ in the string; For all $$$j \geq i$$$, change the value in the $$$j$$$-th position to the opposite, that is, if $$$s_j = 1$$$, then make $$$s_j = 0$$$, and vice versa.What is the minimum number of operations needed to make the string non-decreasing?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"386"You are given an array $$$a$$$ of $$$n$$$ positive integers.You can use the following operation as many times as you like: select any integer $$$1 \le k \le n$$$ and do one of two things:   decrement by one $$$k$$$ of the first elements of the array.  decrement by one $$$k$$$ of the last elements of the array. For example, if $$$n=5$$$ and $$$a=[3,2,2,1,4]$$$, then you can apply one of the following operations to it (not all possible options are listed below):   decrement from the first two elements of the array. After this operation $$$a=[2, 1, 2, 1, 4]$$$;  decrement from the last three elements of the array. After this operation $$$a=[3, 2, 1, 0, 3]$$$;  decrement from the first five elements of the array. After this operation $$$a=[2, 1, 1, 0, 3]$$$; Determine if it is possible to make all the elements of the array equal to zero by applying a certain number of operations.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"387"Diamond Miner is a game that is similar to Gold Miner, but there are $$$n$$$ miners instead of $$$1$$$ in this game.The mining area can be described as a plane. The $$$n$$$ miners can be regarded as $$$n$$$ points on the y-axis. There are $$$n$$$ diamond mines in the mining area. We can regard them as $$$n$$$ points on the x-axis. For some reason, no miners or diamond mines can be at the origin (point $$$(0, 0)$$$). Every miner should mine exactly one diamond mine. Every miner has a hook, which can be used to mine a diamond mine. If a miner at the point $$$(a,b)$$$ uses his hook to mine a diamond mine at the point $$$(c,d)$$$, he will spend $$$\sqrt{(a-c)^2+(b-d)^2}$$$ energy to mine it (the distance between these points). The miners can't move or help each other.The object of this game is to minimize the sum of the energy that miners spend. Can you find this minimum?","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"388"You are given two arrays A and B consisting of integers, sorted in non-decreasing order. Check whether it is possible to choose k numbers in array A and choose m numbers in array B so that any number chosen in the first array is strictly less than any number chosen in the second array.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"389"Valera considers a number beautiful, if it equals 2k or -2k for some integer k (k ≥ 0). Recently, the math teacher asked Valera to represent number n as the sum of beautiful numbers. As Valera is really greedy, he wants to complete the task using as few beautiful numbers as possible. Help Valera and find, how many numbers he is going to need. In other words, if you look at all decompositions of the number n into beautiful summands, you need to find the size of the decomposition which has the fewest summands.","['games', 'number theory']","[1, 0, 0, 0, 1, 0, 0, 0]"390"Let $$$s(x)$$$ be sum of digits in decimal representation of positive integer $$$x$$$. Given two integers $$$n$$$ and $$$m$$$, find some positive integers $$$a$$$ and $$$b$$$ such that   $$$s(a) \ge n$$$,  $$$s(b) \ge n$$$,  $$$s(a + b) \le m$$$. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"391"An online contest will soon be held on ForceCoders, a large competitive programming platform. The authors have prepared $$$n$$$ problems; and since the platform is very popular, $$$998244351$$$ coder from all over the world is going to solve them.For each problem, the authors estimated the number of people who would solve it: for the $$$i$$$-th problem, the number of accepted solutions will be between $$$l_i$$$ and $$$r_i$$$, inclusive.The creator of ForceCoders uses different criteria to determine if the contest is good or bad. One of these criteria is the number of inversions in the problem order. An inversion is a pair of problems $$$(x, y)$$$ such that $$$x$$$ is located earlier in the contest ($$$x < y$$$), but the number of accepted solutions for $$$y$$$ is strictly greater.Obviously, both the creator of ForceCoders and the authors of the contest want the contest to be good. Now they want to calculate the probability that there will be no inversions in the problem order, assuming that for each problem $$$i$$$, any integral number of accepted solutions for it (between $$$l_i$$$ and $$$r_i$$$) is equally probable, and all these numbers are independent.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"392"According to a new ISO standard, a flag of every country should have, strangely enough, a chequered field n × m, each square should be wholly painted one of 26 colours. The following restrictions are set:   In each row at most two different colours can be used.  No two adjacent squares can be painted the same colour. Pay attention, please, that in one column more than two different colours can be used.Berland's government took a decision to introduce changes into their country's flag in accordance with the new standard, at the same time they want these changes to be minimal. By the given description of Berland's flag you should find out the minimum amount of squares that need to be painted different colour to make the flag meet the new ISO standard. You are as well to build one of the possible variants of the new Berland's flag.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"393"INTERCAL is the oldest of esoteric programming languages. One of its many weird features is the method of character-based output, known as Turing Tape method. It converts an array of unsigned 8-bit integers into a sequence of characters to print, using the following method.The integers of the array are processed one by one, starting from the first. Processing i-th element of the array is done in three steps:1. The 8-bit binary notation of the ASCII-code of the previous printed character is reversed. When the first element of the array is processed, the result of this step is considered to be 0.2. The i-th element of the array is subtracted from the result of the previous step modulo 256.3. The binary notation of the result of the previous step is reversed again to produce ASCII-code of the i-th character to be printed.You are given the text printed using this method. Restore the array used to produce this text.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"394"One Big Software Company has n employees numbered from 1 to n. The director is assigned number 1. Every employee of the company except the director has exactly one immediate superior. The director, of course, doesn't have a superior.We will call person a a subordinates of another person b, if either b is an immediate supervisor of a, or the immediate supervisor of a is a subordinate to person b. In particular, subordinates of the head are all other employees of the company.To solve achieve an Important Goal we need to form a workgroup. Every person has some efficiency, expressed by a positive integer ai, where i is the person's number. The efficiency of the workgroup is defined as the total efficiency of all the people included in it.The employees of the big software company are obsessed with modern ways of work process organization. Today pair programming is at the peak of popularity, so the workgroup should be formed with the following condition. Each person entering the workgroup should be able to sort all of his subordinates who are also in the workgroup into pairs. In other words, for each of the members of the workgroup the number of his subordinates within the workgroup should be even.Your task is to determine the maximum possible efficiency of the workgroup formed at observing the given condition. Any person including the director of company can enter the workgroup.","['graphs', 'strings', 'trees']","[0, 0, 1, 0, 0, 0, 1, 1]"395"You are given two segments $$$[l_1; r_1]$$$ and $$$[l_2; r_2]$$$ on the $$$x$$$-axis. It is guaranteed that $$$l_1 < r_1$$$ and $$$l_2 < r_2$$$. Segments may intersect, overlap or even coincide with each other.    The example of two segments on the $$$x$$$-axis. Your problem is to find two integers $$$a$$$ and $$$b$$$ such that $$$l_1 \le a \le r_1$$$, $$$l_2 \le b \le r_2$$$ and $$$a \ne b$$$. In other words, you have to choose two distinct integer points in such a way that the first point belongs to the segment $$$[l_1; r_1]$$$ and the second one belongs to the segment $$$[l_2; r_2]$$$.It is guaranteed that the answer exists. If there are multiple answers, you can print any of them.You have to answer $$$q$$$ independent queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"396"You are given a string $$$s[1 \dots n]$$$ consisting of lowercase Latin letters. It is guaranteed that $$$n = 2^k$$$ for some integer $$$k \ge 0$$$.The string $$$s[1 \dots n]$$$ is called $$$c$$$-good if at least one of the following three conditions is satisfied:  The length of $$$s$$$ is $$$1$$$, and it consists of the character $$$c$$$ (i.e. $$$s_1=c$$$); The length of $$$s$$$ is greater than $$$1$$$, the first half of the string consists of only the character $$$c$$$ (i.e. $$$s_1=s_2=\dots=s_{\frac{n}{2}}=c$$$) and the second half of the string (i.e. the string $$$s_{\frac{n}{2} + 1}s_{\frac{n}{2} + 2} \dots s_n$$$) is a $$$(c+1)$$$-good string;  The length of $$$s$$$ is greater than $$$1$$$, the second half of the string consists of only the character $$$c$$$ (i.e. $$$s_{\frac{n}{2} + 1}=s_{\frac{n}{2} + 2}=\dots=s_n=c$$$) and the first half of the string (i.e. the string $$$s_1s_2 \dots s_{\frac{n}{2}}$$$) is a $$$(c+1)$$$-good string. For example: ""aabc"" is 'a'-good, ""ffgheeee"" is 'e'-good.In one move, you can choose one index $$$i$$$ from $$$1$$$ to $$$n$$$ and replace $$$s_i$$$ with any lowercase Latin letter (any character from 'a' to 'z').Your task is to find the minimum number of moves required to obtain an 'a'-good string from $$$s$$$ (i.e. $$$c$$$-good string for $$$c=$$$ 'a'). It is guaranteed that the answer always exists.You have to answer $$$t$$$ independent test cases.Another example of an 'a'-good string is as follows. Consider the string $$$s = $$$""cdbbaaaa"". It is an 'a'-good string, because:  the second half of the string (""aaaa"") consists of only the character 'a';  the first half of the string (""cdbb"") is 'b'-good string, because:   the second half of the string (""bb"") consists of only the character 'b';  the first half of the string (""cd"") is 'c'-good string, because:   the first half of the string (""c"") consists of only the character 'c';  the second half of the string (""d"") is 'd'-good string.   ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"397"There is an infinite pond that can be represented with a number line. There are $$$n$$$ rocks in the pond, numbered from $$$1$$$ to $$$n$$$. The $$$i$$$-th rock is located at an integer coordinate $$$a_i$$$. The coordinates of the rocks are pairwise distinct. The rocks are numbered in the increasing order of the coordinate, so $$$a_1 < a_2 < \dots < a_n$$$.A robot frog sits on the rock number $$$s$$$. The frog is programmable. It has a base jumping distance parameter $$$d$$$. There also is a setting for the jumping distance range. If the jumping distance range is set to some integer $$$k$$$, then the frog can jump from some rock to any rock at a distance from $$$d - k$$$ to $$$d + k$$$ inclusive in any direction. The distance between two rocks is an absolute difference between their coordinates.You are assigned a task to implement a feature for the frog. Given two integers $$$i$$$ and $$$k$$$ determine if the frog can reach a rock number $$$i$$$ from a rock number $$$s$$$ performing a sequence of jumps with the jumping distance range set to $$$k$$$. The sequence can be arbitrarily long or empty.You will be given $$$q$$$ testcases for that feature, the $$$j$$$-th testcase consists of two integers $$$i$$$ and $$$k$$$. Print ""Yes"" if the $$$i$$$-th rock is reachable and ""No"" otherwise.You can output ""YES"" and ""NO"" in any case (for example, strings ""yEs"", ""yes"", ""Yes"" and 'YES""' will be recognized as a positive answer).",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"398"This is the easier version of the problem. In this version $$$1 \le n, m \le 100$$$. You can hack this problem only if you solve and lock both problems.You are given a sequence of integers $$$a=[a_1,a_2,\dots,a_n]$$$ of length $$$n$$$. Its subsequence is obtained by removing zero or more elements from the sequence $$$a$$$ (they do not necessarily go consecutively). For example, for the sequence $$$a=[11,20,11,33,11,20,11]$$$:  $$$[11,20,11,33,11,20,11]$$$, $$$[11,20,11,33,11,20]$$$, $$$[11,11,11,11]$$$, $$$[20]$$$, $$$[33,20]$$$ are subsequences (these are just some of the long list);  $$$[40]$$$, $$$[33,33]$$$, $$$[33,20,20]$$$, $$$[20,20,11,11]$$$ are not subsequences. Suppose that an additional non-negative integer $$$k$$$ ($$$1 \le k \le n$$$) is given, then the subsequence is called optimal if:  it has a length of $$$k$$$ and the sum of its elements is the maximum possible among all subsequences of length $$$k$$$;  and among all subsequences of length $$$k$$$ that satisfy the previous item, it is lexicographically minimal. Recall that the sequence $$$b=[b_1, b_2, \dots, b_k]$$$ is lexicographically smaller than the sequence $$$c=[c_1, c_2, \dots, c_k]$$$ if the first element (from the left) in which they differ less in the sequence $$$b$$$ than in $$$c$$$. Formally: there exists $$$t$$$ ($$$1 \le t \le k$$$) such that $$$b_1=c_1$$$, $$$b_2=c_2$$$, ..., $$$b_{t-1}=c_{t-1}$$$ and at the same time $$$b_t<c_t$$$. For example:  $$$[10, 20, 20]$$$ lexicographically less than $$$[10, 21, 1]$$$,  $$$[7, 99, 99]$$$ is lexicographically less than $$$[10, 21, 1]$$$,  $$$[10, 21, 0]$$$ is lexicographically less than $$$[10, 21, 1]$$$. You are given a sequence of $$$a=[a_1,a_2,\dots,a_n]$$$ and $$$m$$$ requests, each consisting of two numbers $$$k_j$$$ and $$$pos_j$$$ ($$$1 \le k \le n$$$, $$$1 \le pos_j \le k_j$$$). For each query, print the value that is in the index $$$pos_j$$$ of the optimal subsequence of the given sequence $$$a$$$ for $$$k=k_j$$$.For example, if $$$n=4$$$, $$$a=[10,20,30,20]$$$, $$$k_j=2$$$, then the optimal subsequence is $$$[20,30]$$$ — it is the minimum lexicographically among all subsequences of length $$$2$$$ with the maximum total sum of items. Thus, the answer to the request $$$k_j=2$$$, $$$pos_j=1$$$ is the number $$$20$$$, and the answer to the request $$$k_j=2$$$, $$$pos_j=2$$$ is the number $$$30$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"399"Suppose you are given a string $$$s$$$ of length $$$n$$$ consisting of lowercase English letters. You need to compress it using the smallest possible number of coins.To compress the string, you have to represent $$$s$$$ as a concatenation of several non-empty strings: $$$s = t_{1} t_{2} \ldots t_{k}$$$. The $$$i$$$-th of these strings should be encoded with one of the two ways:  if $$$|t_{i}| = 1$$$, meaning that the current string consists of a single character, you can encode it paying $$$a$$$ coins;  if $$$t_{i}$$$ is a substring of $$$t_{1} t_{2} \ldots t_{i - 1}$$$, then you can encode it paying $$$b$$$ coins. A string $$$x$$$ is a substring of a string $$$y$$$ if $$$x$$$ can be obtained from $$$y$$$ by deletion of several (possibly, zero or all) characters from the beginning and several (possibly, zero or all) characters from the end.So your task is to calculate the minimum possible number of coins you need to spend in order to compress the given string $$$s$$$.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"400"For a given sequence of distinct non-negative integers $$$(b_1, b_2, \dots, b_k)$$$ we determine if it is good in the following way:  Consider a graph on $$$k$$$ nodes, with numbers from $$$b_1$$$ to $$$b_k$$$ written on them. For every $$$i$$$ from $$$1$$$ to $$$k$$$: find such $$$j$$$ ($$$1 \le j \le k$$$, $$$j\neq i$$$), for which $$$(b_i \oplus b_j)$$$ is the smallest among all such $$$j$$$, where $$$\oplus$$$ denotes the operation of bitwise XOR (https://en.wikipedia.org/wiki/Bitwise_operation#XOR). Next, draw an undirected edge between vertices with numbers $$$b_i$$$ and $$$b_j$$$ in this graph. We say that the sequence is good if and only if the resulting graph forms a tree (is connected and doesn't have any simple cycles). It is possible that for some numbers $$$b_i$$$ and $$$b_j$$$, you will try to add the edge between them twice. Nevertheless, you will add this edge only once.You can find an example below (the picture corresponding to the first test case). Sequence $$$(0, 1, 5, 2, 6)$$$ is not good as we cannot reach $$$1$$$ from $$$5$$$.However, sequence $$$(0, 1, 5, 2)$$$ is good.   You are given a sequence $$$(a_1, a_2, \dots, a_n)$$$ of distinct non-negative integers. You would like to remove some of the elements (possibly none) to make the remaining sequence good. What is the minimum possible number of removals required to achieve this goal?It can be shown that for any sequence, we can remove some number of elements, leaving at least $$$2$$$, so that the remaining sequence is good.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"401"You have a square chessboard of size $$$n \times n$$$. Rows are numbered from top to bottom with numbers from $$$1$$$ to $$$n$$$, and columns — from left to right with numbers from $$$1$$$ to $$$n$$$. So, each cell is denoted with pair of integers $$$(x, y)$$$ ($$$1 \le x, y \le n$$$), where $$$x$$$ is a row number and $$$y$$$ is a column number.You have to perform $$$q$$$ queries of three types:  Put a new rook in cell $$$(x, y)$$$.  Remove a rook from cell $$$(x, y)$$$. It's guaranteed that the rook was put in this cell before.  Check if each cell of subrectangle $$$(x_1, y_1) - (x_2, y_2)$$$ of the board is attacked by at least one rook. Subrectangle is a set of cells $$$(x, y)$$$ such that for each cell two conditions are satisfied: $$$x_1 \le x \le x_2$$$ and $$$y_1 \le y \le y_2$$$.Recall that cell $$$(a, b)$$$ is attacked by a rook placed in cell $$$(c, d)$$$ if either $$$a = c$$$ or $$$b = d$$$. In particular, the cell containing a rook is attacked by this rook.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"402"You have a string $$$s$$$ of length $$$n$$$ consisting of only characters > and <. You may do some operations with this string, for each operation you have to choose some character that still remains in the string. If you choose a character >, the character that comes right after it is deleted (if the character you chose was the last one, nothing happens). If you choose a character <, the character that comes right before it is deleted (if the character you chose was the first one, nothing happens).For example, if we choose character > in string > > < >, the string will become to > > >. And if we choose character < in string > <, the string will become to <.The string is good if there is a sequence of operations such that after performing it only one character will remain in the string. For example, the strings >, > > are good. Before applying the operations, you may remove any number of characters from the given string (possibly none, possibly up to $$$n - 1$$$, but not the whole string). You need to calculate the minimum number of characters to be deleted from string $$$s$$$ so that it becomes good.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"403"Goa'uld Apophis captured Jack O'Neill's team again! Jack himself was able to escape, but by that time Apophis's ship had already jumped to hyperspace. But Jack knows on what planet will Apophis land. In order to save his friends, Jack must repeatedly go through stargates to get to this planet.Overall the galaxy has n planets, indexed with numbers from 1 to n. Jack is on the planet with index 1, and Apophis will land on the planet with index n. Jack can move between some pairs of planets through stargates (he can move in both directions); the transfer takes a positive, and, perhaps, for different pairs of planets unequal number of seconds. Jack begins his journey at time 0.It can be that other travellers are arriving to the planet where Jack is currently located. In this case, Jack has to wait for exactly 1 second before he can use the stargate. That is, if at time t another traveller arrives to the planet, Jack can only pass through the stargate at time t + 1, unless there are more travellers arriving at time t + 1 to the same planet.Knowing the information about travel times between the planets, and the times when Jack would not be able to use the stargate on particular planets, determine the minimum time in which he can get to the planet with index n.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"404"This is an interactive problem.I want to play a game with you...We hid from you a cyclic graph of $$$n$$$ vertices ($$$3 \le n \le 10^{18}$$$). A cyclic graph is an undirected graph of $$$n$$$ vertices that form one cycle. Each vertex belongs to the cycle, i.e. the length of the cycle (the number of edges in it) is exactly $$$n$$$. The order of the vertices in the cycle is arbitrary.You can make queries in the following way: ""? a b"" where $$$1 \le a, b \le 10^{18}$$$ and $$$a \neq b$$$. In response to the query, the interactor outputs on a separate line the length of random of two paths from vertex $$$a$$$ to vertex $$$b$$$, or -1 if $$$\max(a, b) > n$$$. The interactor chooses one of the two paths with equal probability. The length of the path —is the number of edges in it.You win if you guess the number of vertices in the hidden graph (number $$$n$$$) by making no more than $$$50$$$ queries.Note that the interactor is implemented in such a way that for any ordered pair $$$(a, b)$$$, it always returns the same value for query ""? a b"", no matter how many such queries. Note that the ""? b a"" query may be answered differently by the interactor.The vertices in the graph are randomly placed, and their positions are fixed in advance.Hacks are forbidden in this problem. The number of tests the jury has is $$$50$$$.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"405"It's a walking tour day in SIS.Winter, so $$$t$$$ groups of students are visiting Torzhok. Streets of Torzhok are so narrow that students have to go in a row one after another.Initially, some students are angry. Let's describe a group of students by a string of capital letters ""A"" and ""P"":   ""A"" corresponds to an angry student  ""P"" corresponds to a patient student Such string describes the row from the last to the first student.Every minute every angry student throws a snowball at the next student. Formally, if an angry student corresponds to the character with index $$$i$$$ in the string describing a group then they will throw a snowball at the student that corresponds to the character with index $$$i+1$$$ (students are given from the last to the first student). If the target student was not angry yet, they become angry. Even if the first (the rightmost in the string) student is angry, they don't throw a snowball since there is no one in front of them.Let's look at the first example test. The row initially looks like this: PPAP. Then, after a minute the only single angry student will throw a snowball at the student in front of them, and they also become angry: PPAA. After that, no more students will become angry.Your task is to help SIS.Winter teachers to determine the last moment a student becomes angry for every group.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"406"A company has n employees numbered from 1 to n. Each employee either has no immediate manager or exactly one immediate manager, who is another employee with a different number. An employee A is said to be the superior of another employee B if at least one of the following is true:  Employee A is the immediate manager of employee B  Employee B has an immediate manager employee C such that employee A is the superior of employee C. The company will not have a managerial cycle. That is, there will not exist an employee who is the superior of his/her own immediate manager.Today the company is going to arrange a party. This involves dividing all n employees into several groups: every employee must belong to exactly one group. Furthermore, within any single group, there must not be two employees A and B such that A is the superior of B.What is the minimum number of groups that must be formed?","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"407"ZS the Coder and Chris the Baboon are travelling to Udayland! To get there, they have to get on the special IOI bus. The IOI bus has n rows of seats. There are 4 seats in each row, and the seats are separated into pairs by a walkway. When ZS and Chris came, some places in the bus was already occupied.ZS and Chris are good friends. They insist to get a pair of neighbouring empty seats. Two seats are considered neighbouring if they are in the same row and in the same pair. Given the configuration of the bus, can you help ZS and Chris determine where they should sit?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"408"Misha and Grisha are funny boys, so they like to use new underground. The underground has n stations connected with n - 1 routes so that each route connects two stations, and it is possible to reach every station from any other.The boys decided to have fun and came up with a plan. Namely, in some day in the morning Misha will ride the underground from station s to station f by the shortest path, and will draw with aerosol an ugly text ""Misha was here"" on every station he will pass through (including s and f). After that on the same day at evening Grisha will ride from station t to station f by the shortest path and will count stations with Misha's text. After that at night the underground workers will wash the texts out, because the underground should be clean. The boys have already chosen three stations a, b and c for each of several following days, one of them should be station s on that day, another should be station f, and the remaining should be station t. They became interested how they should choose these stations s, f, t so that the number Grisha will count is as large as possible. They asked you for help.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"409"Monocarp has got two strings $$$s$$$ and $$$t$$$ having equal length. Both strings consist of lowercase Latin letters ""a"" and ""b"". Monocarp wants to make these two strings $$$s$$$ and $$$t$$$ equal to each other. He can do the following operation any number of times: choose an index $$$pos_1$$$ in the string $$$s$$$, choose an index $$$pos_2$$$ in the string $$$t$$$, and swap $$$s_{pos_1}$$$ with $$$t_{pos_2}$$$.You have to determine the minimum number of operations Monocarp has to perform to make $$$s$$$ and $$$t$$$ equal, and print any optimal sequence of operations — or say that it is impossible to make these strings equal.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"410"Little Petya loves looking for numbers' divisors. One day Petya came across the following problem:You are given n queries in the form ""xi yi"". For each query Petya should count how many divisors of number xi divide none of the numbers xi - yi, xi - yi + 1, ..., xi - 1. Help him.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"411"Vanya walks late at night along a straight street of length l, lit by n lanterns. Consider the coordinate system with the beginning of the street corresponding to the point 0, and its end corresponding to the point l. Then the i-th lantern is at the point ai. The lantern lights all points of the street that are at the distance of at most d from it, where d is some positive number, common for all lanterns. Vanya wonders: what is the minimum light radius d should the lanterns have to light the whole street?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"412"The store sells $$$n$$$ beads. The color of each bead is described by a lowercase letter of the English alphabet (""a""–""z""). You want to buy some beads to assemble a necklace from them.A necklace is a set of beads connected in a circle.For example, if the store sells beads ""a"", ""b"", ""c"", ""a"", ""c"", ""c"", then you can assemble the following necklaces (these are not all possible options):  And the following necklaces cannot be assembled from beads sold in the store:  The first necklace cannot be assembled because it has three beads ""a"" (of the two available). The second necklace cannot be assembled because it contains a bead ""d"", which is not sold in the store. We call a necklace $$$k$$$-beautiful if, when it is turned clockwise by $$$k$$$ beads, the necklace remains unchanged. For example, here is a sequence of three turns of a necklace.    As you can see, this necklace is, for example, $$$3$$$-beautiful, $$$6$$$-beautiful, $$$9$$$-beautiful, and so on, but it is not $$$1$$$-beautiful or $$$2$$$-beautiful.In particular, a necklace of length $$$1$$$ is $$$k$$$-beautiful for any integer $$$k$$$. A necklace that consists of beads of the same color is also beautiful for any $$$k$$$.You are given the integers $$$n$$$ and $$$k$$$, and also the string $$$s$$$ containing $$$n$$$ lowercase letters of the English alphabet — each letter defines a bead in the store. You can buy any subset of beads and connect them in any order. Find the maximum length of a $$$k$$$-beautiful necklace you can assemble.","['graphs', 'number theory']","[0, 0, 1, 0, 1, 0, 0, 0]"413"Among Johnny's numerous hobbies, there are two seemingly harmless ones: applying bitwise operations and sneaking into his dad's office. As it is usually the case with small children, Johnny is unaware that combining these two activities can get him in a lot of trouble.There is a set $$$S$$$ containing very important numbers on his dad's desk. The minute Johnny heard about it, he decided that it's a good idea to choose a positive integer $$$k$$$ and replace each element $$$s$$$ of the set $$$S$$$ with $$$s \oplus k$$$ ($$$\oplus$$$ denotes the exclusive or operation). Help him choose such $$$k$$$ that Johnny's dad will not see any difference after his son is done playing (i.e. Johnny will get the same set as before playing). It is possible that no such number exists. It is also possible that there are many of them. In such a case, output the smallest one. Note that the order of elements in a set doesn't matter, i.e. set $$$\{1, 2, 3\}$$$ equals to set $$$\{2, 1, 3\}$$$.Formally, find the smallest positive integer $$$k$$$ such that $$$\{s \oplus k | s \in S\} = S$$$ or report that there is no such number.For example, if $$$S = \{1, 3, 4\}$$$ and $$$k = 2$$$, new set will be equal to $$$\{3, 1, 6\}$$$. If $$$S = \{0, 1, 2, 3\}$$$ and $$$k = 1$$$, after playing set will stay the same.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"414"You are given n numbers a1, a2, ..., an. You can perform at most k operations. For each operation you can multiply one of the numbers by x. We want to make  as large as possible, where  denotes the bitwise OR. Find the maximum possible value of  after performing at most k operations optimally.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"415"You are given a string s of length n consisting of lowercase English letters.For two given strings s and t, say S is the set of distinct characters of s and T is the set of distinct characters of t. The strings s and t are isomorphic if their lengths are equal and there is a one-to-one mapping (bijection) f between S and T for which f(si) = ti. Formally:  f(si) = ti for any index i,  for any character  there is exactly one character  that f(x) = y,  for any character  there is exactly one character  that f(x) = y. For example, the strings ""aababc"" and ""bbcbcz"" are isomorphic. Also the strings ""aaaww"" and ""wwwaa"" are isomorphic. The following pairs of strings are not isomorphic: ""aab"" and ""bbb"", ""test"" and ""best"".You have to handle m queries characterized by three integers x, y, len (1 ≤ x, y ≤ n - len + 1). For each query check if two substrings s[x... x + len - 1] and s[y... y + len - 1] are isomorphic.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"416"Peter decided to lay a parquet in the room of size n × m, the parquet consists of tiles of size 1 × 2. When the workers laid the parquet, it became clear that the tiles pattern looks not like Peter likes, and workers will have to re-lay it.The workers decided that removing entire parquet and then laying it again is very difficult task, so they decided to make such an operation every hour: remove two tiles, which form a 2 × 2 square, rotate them 90 degrees and put them back on the same place.  They have no idea how to obtain the desired configuration using these operations, and whether it is possible at all.Help Peter to make a plan for the workers or tell that it is impossible. The plan should contain at most 100 000 commands.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"417"You are given an array of integers. Vasya can permute (change order) its integers. He wants to do it so that as many as possible integers will become on a place where a smaller integer used to stand. Help Vasya find the maximal number of such integers.For instance, if we are given an array $$$[10, 20, 30, 40]$$$, we can permute it so that it becomes $$$[20, 40, 10, 30]$$$. Then on the first and the second positions the integers became larger ($$$20>10$$$, $$$40>20$$$) and did not on the third and the fourth, so for this permutation, the number that Vasya wants to maximize equals $$$2$$$. Read the note for the first example, there is one more demonstrative test case.Help Vasya to permute integers in such way that the number of positions in a new array, where integers are greater than in the original one, is maximal.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"418"Ivan wants to write a letter to his friend. The letter is a string s consisting of lowercase Latin letters.Unfortunately, when Ivan started writing the letter, he realised that it is very long and writing the whole letter may take extremely long time. So he wants to write the compressed version of string s instead of the string itself.The compressed version of string s is a sequence of strings c1, s1, c2, s2, ..., ck, sk, where ci is the decimal representation of number ai (without any leading zeroes) and si is some string consisting of lowercase Latin letters. If Ivan writes string s1 exactly a1 times, then string s2 exactly a2 times, and so on, the result will be string s.The length of a compressed version is |c1| + |s1| + |c2| + |s2|... |ck| + |sk|. Among all compressed versions Ivan wants to choose a version such that its length is minimum possible. Help Ivan to determine minimum possible length.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"419"You are given a positive integer $$$n$$$. Let's call some positive integer $$$a$$$ without leading zeroes palindromic if it remains the same after reversing the order of its digits. Find the number of distinct ways to express $$$n$$$ as a sum of positive palindromic integers. Two ways are considered different if the frequency of at least one palindromic integer is different in them. For example, $$$5=4+1$$$ and $$$5=3+1+1$$$ are considered different but $$$5=3+1+1$$$ and $$$5=1+3+1$$$ are considered the same. Formally, you need to find the number of distinct multisets of positive palindromic integers the sum of which is equal to $$$n$$$.Since the answer can be quite large, print it modulo $$$10^9+7$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"420"Keshi is throwing a party and he wants everybody in the party to be happy.He has $$$n$$$ friends. His $$$i$$$-th friend has $$$i$$$ dollars. If you invite the $$$i$$$-th friend to the party, he will be happy only if at most $$$a_i$$$ people in the party are strictly richer than him and at most $$$b_i$$$ people are strictly poorer than him.Keshi wants to invite as many people as possible. Find the maximum number of people he can invite to the party so that every invited person would be happy.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"421"You are organizing a boxing tournament, where $$$n$$$ boxers will participate ($$$n$$$ is a power of $$$2$$$), and your friend is one of them. All boxers have different strength from $$$1$$$ to $$$n$$$, and boxer $$$i$$$ wins in the match against boxer $$$j$$$ if and only if $$$i$$$ is stronger than $$$j$$$.The tournament will be organized as follows: $$$n$$$ boxers will be divided into pairs; the loser in each pair leaves the tournament, and $$$\frac{n}{2}$$$ winners advance to the next stage, where they are divided into pairs again, and the winners in all pairs advance to the next stage, and so on, until only one boxer remains (who is declared the winner).Your friend really wants to win the tournament, but he may be not the strongest boxer. To help your friend win the tournament, you may bribe his opponents: if your friend is fighting with a boxer you have bribed, your friend wins even if his strength is lower.Furthermore, during each stage you distribute the boxers into pairs as you wish.The boxer with strength $$$i$$$ can be bribed if you pay him $$$a_i$$$ dollars. What is the minimum number of dollars you have to spend to make your friend win the tournament, provided that you arrange the boxers into pairs during each stage as you wish?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"422"Unfortunately, Vasya can only sum pairs of integers (a, b), such that for any decimal place at least one number has digit 0 in this place. For example, Vasya can sum numbers 505 and 50, but he cannot sum 1 and 4.Vasya has a set of k distinct non-negative integers d1, d2, ..., dk.Vasya wants to choose some integers from this set so that he could sum any two chosen numbers. What maximal number of integers can he choose in the required manner?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"423"Oh, New Year. The time to gather all your friends and reflect on the heartwarming events of the past year...$$$n$$$ friends live in a city which can be represented as a number line. The $$$i$$$-th friend lives in a house with an integer coordinate $$$x_i$$$. The $$$i$$$-th friend can come celebrate the New Year to the house with coordinate $$$x_i-1$$$, $$$x_i+1$$$ or stay at $$$x_i$$$. Each friend is allowed to move no more than once.For all friends $$$1 \le x_i \le n$$$ holds, however, they can come to houses with coordinates $$$0$$$ and $$$n+1$$$ (if their houses are at $$$1$$$ or $$$n$$$, respectively).For example, let the initial positions be $$$x = [1, 2, 4, 4]$$$. The final ones then can be $$$[1, 3, 3, 4]$$$, $$$[0, 2, 3, 3]$$$, $$$[2, 2, 5, 5]$$$, $$$[2, 1, 3, 5]$$$ and so on. The number of occupied houses is the number of distinct positions among the final ones.So all friends choose the moves they want to perform. After that the number of occupied houses is calculated. What is the minimum and the maximum number of occupied houses can there be?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"424"Two players A and B have a list of $$$n$$$ integers each. They both want to maximize the subtraction between their score and their opponent's score. In one turn, a player can either add to his score any element from his list (assuming his list is not empty), the element is removed from the list afterward. Or remove an element from his opponent's list (assuming his opponent's list is not empty).Note, that in case there are equal elements in the list only one of them will be affected in the operations above. For example, if there are elements $$$\{1, 2, 2, 3\}$$$ in a list and you decided to choose $$$2$$$ for the next turn, only a single instance of $$$2$$$ will be deleted (and added to the score, if necessary). The player A starts the game and the game stops when both lists are empty. Find the difference between A's score and B's score at the end of the game, if both of the players are playing optimally.Optimal play between two players means that both players choose the best possible strategy to achieve the best possible outcome for themselves. In this problem, it means that each player, each time makes a move, which maximizes the final difference between his score and his opponent's score, knowing that the opponent is doing the same.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"425"Once upon a time a little frog whose name was Vasya decided to travel around his home swamp. Overall there are n mounds on the swamp, located on one line. The distance between the neighboring mounds is one meter. Vasya wants to visit all the mounds in one day; besides, he wants to visit each one exactly once. For that he makes a route plan, to decide the order in which to jump on the mounds. Vasya can pick any mound as the first one. He thinks it boring to jump two times at the same distance. That's why he wants any two jumps on his route to have different lengths. Help Vasya the Frog and make the plan for him.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"426"Vasily the bear has got a sequence of positive integers a1, a2, ..., an. Vasily the Bear wants to write out several numbers on a piece of paper so that the beauty of the numbers he wrote out was maximum. The beauty of the written out numbers b1, b2, ..., bk is such maximum non-negative integer v, that number b1 and b2 and ... and bk is divisible by number 2v without a remainder. If such number v doesn't exist (that is, for any non-negative integer v, number b1 and b2 and ... and bk is divisible by 2v without a remainder), the beauty of the written out numbers equals -1. Tell the bear which numbers he should write out so that the beauty of the written out numbers is maximum. If there are multiple ways to write out the numbers, you need to choose the one where the bear writes out as many numbers as possible.Here expression x and y means applying the bitwise AND operation to numbers x and y. In programming languages C++ and Java this operation is represented by ""&"", in Pascal — by ""and"".",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"427"You are given a string $$$s=s_1s_2\dots s_n$$$ of length $$$n$$$, which only contains digits $$$1$$$, $$$2$$$, ..., $$$9$$$.A substring $$$s[l \dots r]$$$ of $$$s$$$ is a string $$$s_l s_{l + 1} s_{l + 2} \ldots s_r$$$. A substring $$$s[l \dots r]$$$ of $$$s$$$ is called even if the number represented by it is even. Find the number of even substrings of $$$s$$$. Note, that even if some substrings are equal as strings, but have different $$$l$$$ and $$$r$$$, they are counted as different substrings.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"428"There are n boxes with colored balls on the table. Colors are numbered from 1 to n. i-th box contains ai balls, all of which have color i. You have to write a program that will divide all balls into sets such that:  each ball belongs to exactly one of the sets,  there are no empty sets,  there is no set containing two (or more) balls of different colors (each set contains only balls of one color),  there are no two sets such that the difference between their sizes is greater than 1. Print the minimum possible number of sets.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"429"An array $$$a_1, a_2, \ldots, a_n$$$ is good if and only if for every subsegment $$$1 \leq l \leq r \leq n$$$, the following holds: $$$a_l + a_{l + 1} + \ldots + a_r = \frac{1}{2}(a_l + a_r) \cdot (r - l + 1)$$$. You are given an array of integers $$$a_1, a_2, \ldots, a_n$$$. In one operation, you can replace any one element of this array with any real number. Find the minimum number of operations you need to make this array good.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"430"Innokentiy decides to change the password in the social net ""Contact!"", but he is too lazy to invent a new password by himself. That is why he needs your help. Innokentiy decides that new password should satisfy the following conditions:  the length of the password must be equal to n,  the password should consist only of lowercase Latin letters,  the number of distinct symbols in the password must be equal to k,  any two consecutive symbols in the password must be distinct. Your task is to help Innokentiy and to invent a new password which will satisfy all given conditions. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"431"You are given a number $$$n$$$ (divisible by $$$3$$$) and an array $$$a[1 \dots n]$$$. In one move, you can increase any of the array elements by one. Formally, you choose the index $$$i$$$ ($$$1 \le i \le n$$$) and replace $$$a_i$$$ with $$$a_i + 1$$$. You can choose the same index $$$i$$$ multiple times for different moves.Let's denote by $$$c_0$$$, $$$c_1$$$ and $$$c_2$$$ the number of numbers from the array $$$a$$$ that have remainders $$$0$$$, $$$1$$$ and $$$2$$$ when divided by the number $$$3$$$, respectively. Let's say that the array $$$a$$$ has balanced remainders if $$$c_0$$$, $$$c_1$$$ and $$$c_2$$$ are equal.For example, if $$$n = 6$$$ and $$$a = [0, 2, 5, 5, 4, 8]$$$, then the following sequence of moves is possible:   initially $$$c_0 = 1$$$, $$$c_1 = 1$$$ and $$$c_2 = 4$$$, these values are not equal to each other. Let's increase $$$a_3$$$, now the array $$$a = [0, 2, 6, 5, 4, 8]$$$;  $$$c_0 = 2$$$, $$$c_1 = 1$$$ and $$$c_2 = 3$$$, these values are not equal. Let's increase $$$a_6$$$, now the array $$$a = [0, 2, 6, 5, 4, 9]$$$;  $$$c_0 = 3$$$, $$$c_1 = 1$$$ and $$$c_2 = 2$$$, these values are not equal. Let's increase $$$a_1$$$, now the array $$$a = [1, 2, 6, 5, 4, 9]$$$;  $$$c_0 = 2$$$, $$$c_1 = 2$$$ and $$$c_2 = 2$$$, these values are equal to each other, which means that the array $$$a$$$ has balanced remainders. Find the minimum number of moves needed to make the array $$$a$$$ have balanced remainders.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"432"Fangy the little walrus, as all the modern walruses, loves to communicate via text messaging. One day he faced the following problem: When he sends large texts, they are split into parts each containing n characters (which is the size of one text message). Thus, whole sentences and words get split!Fangy did not like it, so he faced the task of breaking the text into minimal messages on his own so that no sentence were broken into pieces when it is sent and the number of text messages to be sent would be minimal. If two consecutive sentences are in different messages, the space between them can be ignored (Fangy does not write this space).The little walrus's text looks in the following manner: TEXT ::= SENTENCE | SENTENCE SPACE TEXTSENTENCE ::= WORD SPACE SENTENCE | WORD ENDEND ::= {'.', '?', '!'}WORD ::= LETTER | LETTER WORDLETTER ::= {'a'..'z', 'A'..'Z'}SPACE ::= ' 'SPACE stands for the symbol of a space.So, how many messages did Fangy send?",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"433"You are given a integer $$$n$$$ ($$$n > 0$$$). Find any integer $$$s$$$ which satisfies these conditions, or report that there are no such numbers:In the decimal representation of $$$s$$$:   $$$s > 0$$$,  $$$s$$$ consists of $$$n$$$ digits,  no digit in $$$s$$$ equals $$$0$$$,  $$$s$$$ is not divisible by any of it's digits. ",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"434"Petya has a rooted tree with an integer written on each vertex. The vertex $$$1$$$ is the root. You are to answer some questions about the tree.A tree is a connected graph without cycles. A rooted tree has a special vertex called the root. The parent of a node $$$v$$$ is the next vertex on the shortest path from $$$v$$$ to the root.Each question is defined by three integers $$$v$$$, $$$l$$$, and $$$k$$$. To get the answer to the question, you need to perform the following steps:   First, write down the sequence of all integers written on the shortest path from the vertex $$$v$$$ to the root (including those written in the $$$v$$$ and the root).  Count the number of times each integer occurs. Remove all integers with less than $$$l$$$ occurrences.  Replace the sequence, removing all duplicates and ordering the elements by the number of occurrences in the original list in increasing order. In case of a tie, you can choose the order of these elements arbitrary.  The answer to the question is the $$$k$$$-th number in the remaining sequence. Note that the answer is not always uniquely determined, because there could be several orderings. Also, it is possible that the length of the sequence on this step is less than $$$k$$$, in this case the answer is $$$-1$$$. For example, if the sequence of integers on the path from $$$v$$$ to the root is $$$[2, 2, 1, 7, 1, 1, 4, 4, 4, 4]$$$, $$$l = 2$$$ and $$$k = 2$$$, then the answer is $$$1$$$.Please answer all questions about the tree.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"435"You are given a text consisting of $$$n$$$ space-separated words. There is exactly one space character between any pair of adjacent words. There are no spaces before the first word and no spaces after the last word. The length of text is the number of letters and spaces in it. $$$w_i$$$ is the $$$i$$$-th word of text. All words consist only of lowercase Latin letters.Let's denote a segment of words $$$w[i..j]$$$ as a sequence of words $$$w_i, w_{i + 1}, \dots, w_j$$$. Two segments of words $$$w[i_1 .. j_1]$$$ and $$$w[i_2 .. j_2]$$$ are considered equal if $$$j_1 - i_1 = j_2 - i_2$$$, $$$j_1 \ge i_1$$$, $$$j_2 \ge i_2$$$, and for every $$$t \in [0, j_1 - i_1]$$$ $$$w_{i_1 + t} = w_{i_2 + t}$$$. For example, for the text ""to be or not to be"" the segments $$$w[1..2]$$$ and $$$w[5..6]$$$ are equal, they correspond to the words ""to be"".An abbreviation is a replacement of some segments of words with their first uppercase letters. In order to perform an abbreviation, you have to choose at least two non-intersecting equal segments of words, and replace each chosen segment with the string consisting of first letters of the words in the segment (written in uppercase). For example, for the text ""a ab a a b ab a a b c"" you can replace segments of words $$$w[2..4]$$$ and $$$w[6..8]$$$ with an abbreviation ""AAA"" and obtain the text ""a AAA b AAA b c"", or you can replace segments of words $$$w[2..5]$$$ and $$$w[6..9]$$$ with an abbreviation ""AAAB"" and obtain the text ""a AAAB AAAB c"".What is the minimum length of the text after at most one abbreviation?",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"436"Vus the Cossack has a simple graph with $$$n$$$ vertices and $$$m$$$ edges. Let $$$d_i$$$ be a degree of the $$$i$$$-th vertex. Recall that a degree of the $$$i$$$-th vertex is the number of conected edges to the $$$i$$$-th vertex.He needs to remain not more than $$$\lceil \frac{n+m}{2} \rceil$$$ edges. Let $$$f_i$$$ be the degree of the $$$i$$$-th vertex after removing. He needs to delete them in such way so that $$$\lceil \frac{d_i}{2} \rceil \leq f_i$$$ for each $$$i$$$. In other words, the degree of each vertex should not be reduced more than twice. Help Vus to remain the needed edges!",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"437"As you know, the most intelligent beings on the Earth are, of course, cows. This conclusion was reached long ago by the Martian aliens, as well as a number of other intelligent civilizations from outer space. Sometimes cows gather into cowavans. This seems to be seasonal. But at this time the cows become passive and react poorly to external stimuli. A cowavan is a perfect target for the Martian scientific saucer, it's time for large-scale abductions, or, as the Martians say, raids. Simply put, a cowavan is a set of cows in a row. If we number all cows in the cowavan with positive integers from 1 to n, then we can formalize the popular model of abduction, known as the (a, b)-Cowavan Raid: first they steal a cow number a, then number a + b, then — number a + 2·b, and so on, until the number of an abducted cow exceeds n. During one raid the cows are not renumbered. The aliens would be happy to place all the cows on board of their hospitable ship, but unfortunately, the amount of cargo space is very, very limited. The researchers, knowing the mass of each cow in the cowavan, made p scenarios of the (a, b)-raid. Now they want to identify the following thing for each scenario individually: what total mass of pure beef will get on board of the ship. All the scenarios are independent, in the process of performing the calculations the cows are not being stolen.   ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"438"You are given a connected weighted undirected graph without any loops and multiple edges. Let us remind you that a graph's spanning tree is defined as an acyclic connected subgraph of the given graph that includes all of the graph's vertexes. The weight of a tree is defined as the sum of weights of the edges that the given tree contains. The minimum spanning tree (MST) of a graph is defined as the graph's spanning tree having the minimum possible weight. For any connected graph obviously exists the minimum spanning tree, but in the general case, a graph's minimum spanning tree is not unique.Your task is to determine the following for each edge of the given graph: whether it is either included in any MST, or included at least in one MST, or not included in any MST.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"439"Xenia is a girl being born a noble. Due to the inflexibility and harshness of her family, Xenia has to find some ways to amuse herself. Recently Xenia has bought $$$n_r$$$ red gems, $$$n_g$$$ green gems and $$$n_b$$$ blue gems. Each of the gems has a weight.Now, she is going to pick three gems.Xenia loves colorful things, so she will pick exactly one gem of each color.Xenia loves balance, so she will try to pick gems with little difference in weight.Specifically, supposing the weights of the picked gems are $$$x$$$, $$$y$$$ and $$$z$$$, Xenia wants to find the minimum value of $$$(x-y)^2+(y-z)^2+(z-x)^2$$$. As her dear friend, can you help her?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"440"A permutation of length $$$n$$$ is an array consisting of $$$n$$$ distinct integers from $$$1$$$ to $$$n$$$ in arbitrary order. For example, $$$[2,3,1,5,4]$$$ is a permutation, but $$$[1,2,2]$$$ is not a permutation ($$$2$$$ appears twice in the array) and $$$[1,3,4]$$$ is also not a permutation ($$$n=3$$$ but there is $$$4$$$ in the array).For a positive integer $$$n$$$, we call a permutation $$$p$$$ of length $$$n$$$ good if the following condition holds for every pair $$$i$$$ and $$$j$$$ ($$$1 \le i \le j \le n$$$) —   $$$(p_i \text{ OR } p_{i+1} \text{ OR } \ldots \text{ OR } p_{j-1} \text{ OR } p_{j}) \ge j-i+1$$$, where $$$\text{OR}$$$ denotes the bitwise OR operation. In other words, a permutation $$$p$$$ is good if for every subarray of $$$p$$$, the $$$\text{OR}$$$ of all elements in it is not less than the number of elements in that subarray. Given a positive integer $$$n$$$, output any good permutation of length $$$n$$$. We can show that for the given constraints such a permutation always exists.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"441"Bob has a rectangular chocolate bar of the size W × H. He introduced a cartesian coordinate system so that the point (0, 0) corresponds to the lower-left corner of the bar, and the point (W, H) corresponds to the upper-right corner. Bob decided to split the bar into pieces by breaking it. Each break is a segment parallel to one of the coordinate axes, which connects the edges of the bar. More formally, each break goes along the line x = xc or y = yc, where xc and yc are integers. It should divide one part of the bar into two non-empty parts. After Bob breaks some part into two parts, he breaks the resulting parts separately and independently from each other. Also he doesn't move the parts of the bar. Bob made n breaks and wrote them down in his notebook in arbitrary order. At the end he got n + 1 parts. Now he wants to calculate their areas. Bob is lazy, so he asks you to do this task.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"442"This is an interactive problem. You should use flush operation after each printed line. For example, in C++ you should use fflush(stdout), in Java you should use System.out.flush(), and in Pascal — flush(output).In this problem you should guess an array a which is unknown for you. The only information you have initially is the length n of the array a.The only allowed action is to ask the sum of two elements by their indices. Formally, you can print two indices i and j (the indices should be distinct). Then your program should read the response: the single integer equals to ai + aj.It is easy to prove that it is always possible to guess the array using at most n requests.Write a program that will guess the array a by making at most n requests.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"443"Eugene likes working with arrays. And today he needs your help in solving one challenging task.An array $$$c$$$ is a subarray of an array $$$b$$$ if $$$c$$$ can be obtained from $$$b$$$ by deletion of several (possibly, zero or all) elements from the beginning and several (possibly, zero or all) elements from the end.Let's call a nonempty array good if for every nonempty subarray of this array, sum of the elements of this subarray is nonzero. For example, array $$$[-1, 2, -3]$$$ is good, as all arrays $$$[-1]$$$, $$$[-1, 2]$$$, $$$[-1, 2, -3]$$$, $$$[2]$$$, $$$[2, -3]$$$, $$$[-3]$$$ have nonzero sums of elements. However, array $$$[-1, 2, -1, -3]$$$ isn't good, as his subarray $$$[-1, 2, -1]$$$ has sum of elements equal to $$$0$$$.Help Eugene to calculate the number of nonempty good subarrays of a given array $$$a$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"444"And where the are the phone numbers?You are given a string s consisting of lowercase English letters and an integer k. Find the lexicographically smallest string t of length k, such that its set of letters is a subset of the set of letters of s and s is lexicographically smaller than t.It's guaranteed that the answer exists.Note that the set of letters is a set, not a multiset. For example, the set of letters of abadaba is {a, b, d}.String p is lexicographically smaller than string q, if p is a prefix of q, is not equal to q or there exists i, such that pi < qi and for all j < i it is satisfied that pj = qj. For example, abc is lexicographically smaller than abcd , abd is lexicographically smaller than abec, afa is not lexicographically smaller than ab and a is not lexicographically smaller than a.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"445"Kevin has just recevied his disappointing results on the USA Identification of Cows Olympiad (USAICO) in the form of a binary string of length n. Each character of Kevin's string represents Kevin's score on one of the n questions of the olympiad—'1' for a correctly identified cow and '0' otherwise.However, all is not lost. Kevin is a big proponent of alternative thinking and believes that his score, instead of being the sum of his points, should be the length of the longest alternating subsequence of his string. Here, we define an alternating subsequence of a string as a not-necessarily contiguous subsequence where no two consecutive elements are equal. For example, {0, 1, 0, 1}, {1, 0, 1}, and {1, 0, 1, 0} are alternating sequences, while {1, 0, 0} and {0, 1, 0, 1, 1} are not.Kevin, being the sneaky little puffball that he is, is willing to hack into the USAICO databases to improve his score. In order to be subtle, he decides that he will flip exactly one substring—that is, take a contiguous non-empty substring of his score and change all '0's in that substring to '1's and vice versa. After such an operation, Kevin wants to know the length of the longest possible alternating subsequence that his string could have.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"446"You are walking through a parkway near your house. The parkway has $$$n+1$$$ benches in a row numbered from $$$1$$$ to $$$n+1$$$ from left to right. The distance between the bench $$$i$$$ and $$$i+1$$$ is $$$a_i$$$ meters.Initially, you have $$$m$$$ units of energy. To walk $$$1$$$ meter of distance, you spend $$$1$$$ unit of your energy. You can't walk if you have no energy. Also, you can restore your energy by sitting on benches (and this is the only way to restore the energy). When you are sitting, you can restore any integer amount of energy you want (if you sit longer, you restore more energy). Note that the amount of your energy can exceed $$$m$$$.Your task is to find the minimum amount of energy you have to restore (by sitting on benches) to reach the bench $$$n+1$$$ from the bench $$$1$$$ (and end your walk).You have to answer $$$t$$$ independent test cases.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"447"You are given a permutation $$$a$$$ of size $$$n$$$ and you should perform $$$n$$$ operations on it. In the $$$i$$$-th operation, you can choose a non-empty suffix of $$$a$$$ and increase all of its elements by $$$i$$$. How can we perform the operations to minimize the number of inversions in the final array?Note that you can perform operations on the same suffix any number of times you want.A permutation of size $$$n$$$ is an array of size $$$n$$$ such that each integer from $$$1$$$ to $$$n$$$ occurs exactly once in this array. A suffix is several consecutive elements of an array that include the last element of the array. An inversion in an array $$$a$$$ is a pair of indices $$$(i, j)$$$ such that $$$i > j$$$ and $$$a_{i} < a_{j}$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"448"You are given two integers $$$x$$$ and $$$y$$$. You can perform two types of operations:   Pay $$$a$$$ dollars and increase or decrease any of these integers by $$$1$$$. For example, if $$$x = 0$$$ and $$$y = 7$$$ there are four possible outcomes after this operation:   $$$x = 0$$$, $$$y = 6$$$;  $$$x = 0$$$, $$$y = 8$$$;  $$$x = -1$$$, $$$y = 7$$$;  $$$x = 1$$$, $$$y = 7$$$.   Pay $$$b$$$ dollars and increase or decrease both integers by $$$1$$$. For example, if $$$x = 0$$$ and $$$y = 7$$$ there are two possible outcomes after this operation:   $$$x = -1$$$, $$$y = 6$$$;  $$$x = 1$$$, $$$y = 8$$$.  Your goal is to make both given integers equal zero simultaneously, i.e. $$$x = y = 0$$$. There are no other requirements. In particular, it is possible to move from $$$x=1$$$, $$$y=0$$$ to $$$x=y=0$$$.Calculate the minimum amount of dollars you have to spend on it.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"449"An L-shape is a figure on gridded paper that looks like the first four pictures below. An L-shape contains exactly three shaded cells (denoted by *), which can be rotated in any way.  You are given a rectangular grid. Determine if it contains L-shapes only, where L-shapes can't touch an edge or corner. More formally:   Each shaded cell in the grid is part of exactly one L-shape, and  no two L-shapes are adjacent by edge or corner. For example, the last two grids in the picture above do not satisfy the condition because the two L-shapes touch by corner and edge, respectively.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"450"The teacher gave Anton a large geometry homework, but he didn't do it (as usual) as he participated in a regular round on Codeforces. In the task he was given a set of n lines defined by the equations y = ki·x + bi. It was necessary to determine whether there is at least one point of intersection of two of these lines, that lays strictly inside the strip between x1 < x2. In other words, is it true that there are 1 ≤ i < j ≤ n and x', y', such that:   y' = ki * x' + bi, that is, point (x', y') belongs to the line number i;  y' = kj * x' + bj, that is, point (x', y') belongs to the line number j;  x1 < x' < x2, that is, point (x', y') lies inside the strip bounded by x1 < x2. You can't leave Anton in trouble, can you? Write a program that solves the given task.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"451"Mishka is a little polar bear. As known, little bears loves spending their free time playing dice for chocolates. Once in a wonderful sunny morning, walking around blocks of ice, Mishka met her friend Chris, and they started playing the game.Rules of the game are very simple: at first number of rounds n is defined. In every round each of the players throws a cubical dice with distinct numbers from 1 to 6 written on its faces. Player, whose value after throwing the dice is greater, wins the round. In case if player dice values are equal, no one of them is a winner.In average, player, who won most of the rounds, is the winner of the game. In case if two players won the same number of rounds, the result of the game is draw.Mishka is still very little and can't count wins and losses, so she asked you to watch their game and determine its result. Please help her!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"452"You have $$$n$$$ gifts and you want to give all of them to children. Of course, you don't want to offend anyone, so all gifts should be equal between each other. The $$$i$$$-th gift consists of $$$a_i$$$ candies and $$$b_i$$$ oranges.During one move, you can choose some gift $$$1 \le i \le n$$$ and do one of the following operations:  eat exactly one candy from this gift (decrease $$$a_i$$$ by one);  eat exactly one orange from this gift (decrease $$$b_i$$$ by one);  eat exactly one candy and exactly one orange from this gift (decrease both $$$a_i$$$ and $$$b_i$$$ by one). Of course, you can not eat a candy or orange if it's not present in the gift (so neither $$$a_i$$$ nor $$$b_i$$$ can become less than zero).As said above, all gifts should be equal. This means that after some sequence of moves the following two conditions should be satisfied: $$$a_1 = a_2 = \dots = a_n$$$ and $$$b_1 = b_2 = \dots = b_n$$$ (and $$$a_i$$$ equals $$$b_i$$$ is not necessary).Your task is to find the minimum number of moves required to equalize all the given gifts.You have to answer $$$t$$$ independent test cases.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"453"Alice and Borys are playing tennis.A tennis match consists of games. In each game, one of the players is serving and the other one is receiving.Players serve in turns: after a game where Alice is serving follows a game where Borys is serving, and vice versa.Each game ends with a victory of one of the players. If a game is won by the serving player, it's said that this player holds serve. If a game is won by the receiving player, it's said that this player breaks serve.It is known that Alice won $$$a$$$ games and Borys won $$$b$$$ games during the match. It is unknown who served first and who won which games.Find all values of $$$k$$$ such that exactly $$$k$$$ breaks could happen during the match between Alice and Borys in total.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"454"Allen is hosting a formal dinner party. $$$2n$$$ people come to the event in $$$n$$$ pairs (couples). After a night of fun, Allen wants to line everyone up for a final picture. The $$$2n$$$ people line up, but Allen doesn't like the ordering. Allen prefers if each pair occupies adjacent positions in the line, as this makes the picture more aesthetic.Help Allen find the minimum number of swaps of adjacent positions he must perform to make it so that each couple occupies adjacent positions in the line.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"455"Nadeko's birthday is approaching! As she decorated the room for the party, a long garland of Dianthus-shaped paper pieces was placed on a prominent part of the wall. Brother Koyomi will like it!Still unsatisfied with the garland, Nadeko decided to polish it again. The garland has n pieces numbered from 1 to n from left to right, and the i-th piece has a colour si, denoted by a lowercase English letter. Nadeko will repaint at most m of the pieces to give each of them an arbitrary new colour (still denoted by a lowercase English letter). After this work, she finds out all subsegments of the garland containing pieces of only colour c — Brother Koyomi's favourite one, and takes the length of the longest among them to be the Koyomity of the garland.For instance, let's say the garland is represented by ""kooomo"", and Brother Koyomi's favourite colour is ""o"". Among all subsegments containing pieces of ""o"" only, ""ooo"" is the longest, with a length of 3. Thus the Koyomity of this garland equals 3.But problem arises as Nadeko is unsure about Brother Koyomi's favourite colour, and has swaying ideas on the amount of work to do. She has q plans on this, each of which can be expressed as a pair of an integer mi and a lowercase letter ci, meanings of which are explained above. You are to find out the maximum Koyomity achievable after repainting the garland according to each plan.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"456"You are given n points on the straight line — the positions (x-coordinates) of the cities and m points on the same line — the positions (x-coordinates) of the cellular towers. All towers work in the same way — they provide cellular network for all cities, which are located at the distance which is no more than r from this tower.Your task is to find minimal r that each city has been provided by cellular network, i.e. for each city there is at least one cellular tower at the distance which is no more than r.If r = 0 then a tower provides cellular network only for the point where it is located. One tower can provide cellular network for any number of cities, but all these cities must be at the distance which is no more than r from this tower.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"457"Motorist Kojiro spent 10 years saving up for his favorite car brand, Furrari. Finally Kojiro's dream came true! Kojiro now wants to get to his girlfriend Johanna to show off his car to her.Kojiro wants to get to his girlfriend, so he will go to her along a coordinate line. For simplicity, we can assume that Kojiro is at the point f of a coordinate line, and Johanna is at point e. Some points of the coordinate line have gas stations. Every gas station fills with only one type of fuel: Regular-92, Premium-95 or Super-98. Thus, each gas station is characterized by a pair of integers ti and xi — the number of the gas type and its position.One liter of fuel is enough to drive for exactly 1 km (this value does not depend on the type of fuel). Fuels of three types differ only in quality, according to the research, that affects the lifetime of the vehicle motor. A Furrari tank holds exactly s liters of fuel (regardless of the type of fuel). At the moment of departure from point f Kojiro's tank is completely filled with fuel Super-98. At each gas station Kojiro can fill the tank with any amount of fuel, but of course, at no point in time, the amount of fuel in the tank can be more than s liters. Note that the tank can simultaneously have different types of fuel. The car can moves both left and right.To extend the lifetime of the engine Kojiro seeks primarily to minimize the amount of fuel of type Regular-92. If there are several strategies to go from f to e, using the minimum amount of fuel of type Regular-92, it is necessary to travel so as to minimize the amount of used fuel of type Premium-95.Write a program that can for the m possible positions of the start fi minimize firstly, the amount of used fuel of type Regular-92 and secondly, the amount of used fuel of type Premium-95.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"458"A sequence of brackets is called balanced if one can turn it into a valid math expression by adding characters '+' and '1'. For example, sequences '(())()', '()', and '(()(()))' are balanced, while ')(', '(()', and '(()))(' are not.You are given a binary string $$$s$$$ of length $$$n$$$. Construct two balanced bracket sequences $$$a$$$ and $$$b$$$ of length $$$n$$$ such that for all $$$1\le i\le n$$$:   if $$$s_i=1$$$, then $$$a_i=b_i$$$  if $$$s_i=0$$$, then $$$a_i\ne b_i$$$ If it is impossible, you should report about it.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"459"You are given an array of integers $$$b_1, b_2, \ldots, b_n$$$.An array $$$a_1, a_2, \ldots, a_n$$$ of integers is hybrid if for each $$$i$$$ ($$$1 \leq i \leq n$$$) at least one of these conditions is true:   $$$b_i = a_i$$$, or  $$$b_i = \sum_{j=1}^{i} a_j$$$. Find the number of hybrid arrays $$$a_1, a_2, \ldots, a_n$$$. As the result can be very large, you should print the answer modulo $$$10^9 + 7$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"460"Polycarp is making a quest for his friends. He has already made n tasks, for each task the boy evaluated how interesting it is as an integer qi, and the time ti in minutes needed to complete the task. An interesting feature of his quest is: each participant should get the task that is best suited for him, depending on his preferences. The task is chosen based on an interactive quiz that consists of some questions. The player should answer these questions with ""yes"" or ""no"". Depending on the answer to the question, the participant either moves to another question or goes to one of the tasks that are in the quest. In other words, the quest is a binary tree, its nodes contain questions and its leaves contain tasks. We know that answering any of the questions that are asked before getting a task takes exactly one minute from the quest player. Polycarp knows that his friends are busy people and they can't participate in the quest for more than T minutes. Polycarp wants to choose some of the n tasks he made, invent the corresponding set of questions for them and use them to form an interactive quiz as a binary tree so that no matter how the player answers quiz questions, he spends at most T minutes on completing the whole quest (that is, answering all the questions and completing the task). Specifically, the quest can contain zero questions and go straight to the task. Each task can only be used once (i.e., the people who give different answers to questions should get different tasks).Polycarp wants the total ""interest"" value of the tasks involved in the quest to be as large as possible. Help him determine the maximum possible total interest value of the task considering that the quest should be completed in T minutes at any variant of answering questions.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"461"Lunar New Year is approaching, and Bob decides to take a wander in a nearby park.The park can be represented as a connected graph with $$$n$$$ nodes and $$$m$$$ bidirectional edges. Initially Bob is at the node $$$1$$$ and he records $$$1$$$ on his notebook. He can wander from one node to another through those bidirectional edges. Whenever he visits a node not recorded on his notebook, he records it. After he visits all nodes at least once, he stops wandering, thus finally a permutation of nodes $$$a_1, a_2, \ldots, a_n$$$ is recorded.Wandering is a boring thing, but solving problems is fascinating. Bob wants to know the lexicographically smallest sequence of nodes he can record while wandering. Bob thinks this problem is trivial, and he wants you to solve it.A sequence $$$x$$$ is lexicographically smaller than a sequence $$$y$$$ if and only if one of the following holds:   $$$x$$$ is a prefix of $$$y$$$, but $$$x \ne y$$$ (this is impossible in this problem as all considered sequences have the same length);  in the first position where $$$x$$$ and $$$y$$$ differ, the sequence $$$x$$$ has a smaller element than the corresponding element in $$$y$$$. ",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"462"To improve the boomerang throwing skills of the animals, Zookeeper has set up an $$$n \times n$$$ grid with some targets, where each row and each column has at most $$$2$$$ targets each. The rows are numbered from $$$1$$$ to $$$n$$$ from top to bottom, and the columns are numbered from $$$1$$$ to $$$n$$$ from left to right.  For each column, Zookeeper will throw a boomerang from the bottom of the column (below the grid) upwards. When the boomerang hits any target, it will bounce off, make a $$$90$$$ degree turn to the right and fly off in a straight line in its new direction. The boomerang can hit multiple targets and does not stop until it leaves the grid.   In the above example, $$$n=6$$$ and the black crosses are the targets. The boomerang in column $$$1$$$ (blue arrows) bounces $$$2$$$ times while the boomerang in column $$$3$$$ (red arrows) bounces $$$3$$$ times. The boomerang in column $$$i$$$ hits exactly $$$a_i$$$ targets before flying out of the grid. It is known that $$$a_i \leq 3$$$.However, Zookeeper has lost the original positions of the targets. Thus, he asks you to construct a valid configuration of targets that matches the number of hits for each column, or tell him that no such configuration exists. If multiple valid configurations exist, you may print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"463"You are given an integer m, and a list of n distinct integers between 0 and m - 1.You would like to construct a sequence satisfying the properties:  Each element is an integer between 0 and m - 1, inclusive.  All prefix products of the sequence modulo m are distinct.  No prefix product modulo m appears as an element of the input list.  The length of the sequence is maximized. Construct any sequence satisfying the properties above.","['graphs', 'math', 'number theory']","[0, 0, 1, 1, 1, 0, 0, 0]"464"Æsir - CHAOS Æsir - V.""Everything has been planned out. No more hidden concerns. The condition of Cytus is also perfect.The time right now...... 00:01:12......It's time.""The emotion samples are now sufficient. After almost 3 years, it's time for Ivy to awake her bonded sister, Vanessa.The system inside A.R.C.'s Library core can be considered as an undirected graph with infinite number of processing nodes, numbered with all positive integers ($$$1, 2, 3, \ldots$$$). The node with a number $$$x$$$ ($$$x > 1$$$), is directly connected with a node with number $$$\frac{x}{f(x)}$$$, with $$$f(x)$$$ being the lowest prime divisor of $$$x$$$.Vanessa's mind is divided into $$$n$$$ fragments. Due to more than 500 years of coma, the fragments have been scattered: the $$$i$$$-th fragment is now located at the node with a number $$$k_i!$$$ (a factorial of $$$k_i$$$).To maximize the chance of successful awakening, Ivy decides to place the samples in a node $$$P$$$, so that the total length of paths from each fragment to $$$P$$$ is smallest possible. If there are multiple fragments located at the same node, the path from that node to $$$P$$$ needs to be counted multiple times.In the world of zeros and ones, such a requirement is very simple for Ivy. Not longer than a second later, she has already figured out such a node.But for a mere human like you, is this still possible?For simplicity, please answer the minimal sum of paths' lengths from every fragment to the emotion samples' assembly node $$$P$$$.","['graphs', 'math', 'number theory', 'trees']","[0, 0, 1, 1, 1, 0, 0, 1]"465"You are given an array $$$a$$$ of size $$$n$$$. Each element in this array is an integer between $$$1$$$ and $$$10^9$$$.You can perform several operations to this array. During an operation, you can replace an element in the array with any integer between $$$1$$$ and $$$10^9$$$. Output the minimum number of operations needed such that the resulting array doesn't contain any local maximums, and the resulting array after the operations.An element $$$a_i$$$ is a local maximum if it is strictly larger than both of its neighbors (that is, $$$a_i > a_{i - 1}$$$ and $$$a_i > a_{i + 1}$$$). Since $$$a_1$$$ and $$$a_n$$$ have only one neighbor each, they will never be a local maximum.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"466"Even if it's a really easy question, she won't be able to answer it— Perfect Memento in Strict SenseCirno's perfect bitmasks classroom has just started!Cirno gave her students a positive integer $$$x$$$. As an assignment, her students need to find the minimum positive integer $$$y$$$, which satisfies the following two conditions:$$$$$$x\ \texttt{and}\ y > 0$$$$$$ $$$$$$x\ \texttt{xor}\ y > 0$$$$$$Where $$$\texttt{and}$$$ is the bitwise AND operation, and $$$\texttt{xor}$$$ is the bitwise XOR operation.Among the students was Mystia, who was truly baffled by all these new operators. Please help her!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"467You're given an array $$$a$$$ of length $$$2n$$$. Is it possible to reorder it in such way so that the sum of the first $$$n$$$ elements isn't equal to the sum of the last $$$n$$$ elements?,[],"[0, 0, 0, 0, 0, 0, 0, 0]"468"Dima got into number sequences. Now he's got sequence a1, a2, ..., an, consisting of n positive integers. Also, Dima has got a function f(x), which can be defined with the following recurrence:  f(0) = 0;  f(2·x) = f(x);  f(2·x + 1) = f(x) + 1. Dima wonders, how many pairs of indexes (i, j) (1 ≤ i < j ≤ n) are there, such that f(ai) = f(aj). Help him, count the number of such pairs. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"469"You are given an array $$$a_1, a_2, \dots , a_n$$$. Array is good if for each pair of indexes $$$i < j$$$ the condition $$$j - a_j \ne i - a_i$$$ holds. Can you shuffle this array so that it becomes good? To shuffle an array means to reorder its elements arbitrarily (leaving the initial order is also an option).For example, if $$$a = [1, 1, 3, 5]$$$, then shuffled arrays $$$[1, 3, 5, 1]$$$, $$$[3, 5, 1, 1]$$$ and $$$[5, 3, 1, 1]$$$ are good, but shuffled arrays $$$[3, 1, 5, 1]$$$, $$$[1, 1, 3, 5]$$$ and $$$[1, 1, 5, 3]$$$ aren't.It's guaranteed that it's always possible to shuffle an array to meet this condition.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"470Convexity of a set of points on the plane is the size of the largest subset of points that form a convex polygon. Your task is to build a set of n points with the convexity of exactly m. Your set of points should not contain three points that lie on a straight line.,['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"471"Vasya's telephone contains n photos. Photo number 1 is currently opened on the phone. It is allowed to move left and right to the adjacent photo by swiping finger over the screen. If you swipe left from the first photo, you reach photo n. Similarly, by swiping right from the last photo you reach photo 1. It takes a seconds to swipe from photo to adjacent.For each photo it is known which orientation is intended for it — horizontal or vertical. Phone is in the vertical orientation and can't be rotated. It takes b second to change orientation of the photo.Vasya has T seconds to watch photos. He want to watch as many photos as possible. If Vasya opens the photo for the first time, he spends 1 second to notice all details in it. If photo is in the wrong orientation, he spends b seconds on rotating it before watching it. If Vasya has already opened the photo, he just skips it (so he doesn't spend any time for watching it or for changing its orientation). It is not allowed to skip unseen photos.Help Vasya find the maximum number of photos he is able to watch during T seconds.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"472"As the guys fried the radio station facilities, the school principal gave them tasks as a punishment. Dustin's task was to add comments to nginx configuration for school's website. The school has n servers. Each server has a name and an ip (names aren't necessarily unique, but ips are). Dustin knows the ip and name of each server. For simplicity, we'll assume that an nginx command is of form ""command ip;"" where command is a string consisting of English lowercase letter only, and ip is the ip of one of school servers.  Each ip is of form ""a.b.c.d"" where a, b, c and d are non-negative integers less than or equal to 255 (with no leading zeros). The nginx configuration file Dustin has to add comments to has m commands. Nobody ever memorizes the ips of servers, so to understand the configuration better, Dustin has to comment the name of server that the ip belongs to at the end of each line (after each command). More formally, if a line is ""command ip;"" Dustin has to replace it with ""command ip; #name"" where name is the name of the server with ip equal to ip.Dustin doesn't know anything about nginx, so he panicked again and his friends asked you to do his task for him.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"473"In a galaxy far, far away Lesha the student has just got to know that he has an exam in two days. As always, he hasn't attended any single class during the previous year, so he decided to spend the remaining time wisely.Lesha knows that today he can study for at most $$$a$$$ hours, and he will have $$$b$$$ hours to study tomorrow. Note that it is possible that on his planet there are more hours in a day than on Earth. Lesha knows that the quality of his knowledge will only depend on the number of lecture notes he will read. He has access to an infinite number of notes that are enumerated with positive integers, but he knows that he can read the first note in one hour, the second note in two hours and so on. In other words, Lesha can read the note with number $$$k$$$ in $$$k$$$ hours. Lesha can read the notes in arbitrary order, however, he can't start reading a note in the first day and finish its reading in the second day.Thus, the student has to fully read several lecture notes today, spending at most $$$a$$$ hours in total, and fully read several lecture notes tomorrow, spending at most $$$b$$$ hours in total. What is the maximum number of notes Lesha can read in the remaining time? Which notes should he read in the first day, and which — in the second?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"474"Although Inzane successfully found his beloved bone, Zane, his owner, has yet to return. To search for Zane, he would need a lot of money, of which he sadly has none. To deal with the problem, he has decided to hack the banks.  There are n banks, numbered from 1 to n. There are also n - 1 wires connecting the banks. All banks are initially online. Each bank also has its initial strength: bank i has initial strength ai.Let us define some keywords before we proceed. Bank i and bank j are neighboring if and only if there exists a wire directly connecting them. Bank i and bank j are semi-neighboring if and only if there exists an online bank k such that bank i and bank k are neighboring and bank k and bank j are neighboring.When a bank is hacked, it becomes offline (and no longer online), and other banks that are neighboring or semi-neighboring to it have their strengths increased by 1.To start his plan, Inzane will choose a bank to hack first. Indeed, the strength of such bank must not exceed the strength of his computer. After this, he will repeatedly choose some bank to hack next until all the banks are hacked, but he can continue to hack bank x if and only if all these conditions are met:  Bank x is online. That is, bank x is not hacked yet.  Bank x is neighboring to some offline bank.  The strength of bank x is less than or equal to the strength of Inzane's computer. Determine the minimum strength of the computer Inzane needs to hack all the banks.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"475"Vera adores poems. All the poems Vera knows are divided into quatrains (groups of four lines) and in each quatrain some lines contain rhymes.Let's consider that all lines in the poems consist of lowercase Latin letters (without spaces). Letters ""a"", ""e"", ""i"", ""o"", ""u"" are considered vowels.Two lines rhyme if their suffixes that start from the k-th vowels (counting from the end) match. If a line has less than k vowels, then such line can't rhyme with any other line. For example, if k = 1, lines commit and hermit rhyme (the corresponding suffixes equal it), and if k = 2, they do not rhyme (ommit ≠ ermit).Today on a literature lesson Vera learned that quatrains can contain four different schemes of rhymes, namely the following ones (the same letters stand for rhyming lines):   Clerihew (aabb);  Alternating (abab);  Enclosed (abba). If all lines of a quatrain pairwise rhyme, then the quatrain can belong to any rhyme scheme (this situation is represented by aaaa).If all quatrains of a poem belong to the same rhyme scheme, then we can assume that the whole poem belongs to this rhyme scheme. If in each quatrain all lines pairwise rhyme, then the rhyme scheme of the poem is aaaa. Let us note that it doesn't matter whether lines from different quatrains rhyme with each other or not. In other words, it is possible that different quatrains aren't connected by a rhyme.Vera got a long poem as a home task. The girl has to analyse it and find the poem rhyme scheme. Help Vera cope with the task.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"476"You are given a positive integer $$$D$$$. Let's build the following graph from it:   each vertex is a divisor of $$$D$$$ (not necessarily prime, $$$1$$$ and $$$D$$$ itself are also included);  two vertices $$$x$$$ and $$$y$$$ ($$$x > y$$$) have an undirected edge between them if $$$x$$$ is divisible by $$$y$$$ and $$$\frac x y$$$ is a prime;  the weight of an edge is the number of divisors of $$$x$$$ that are not divisors of $$$y$$$. For example, here is the graph for $$$D=12$$$:   Edge $$$(4,12)$$$ has weight $$$3$$$ because $$$12$$$ has divisors $$$[1,2,3,4,6,12]$$$ and $$$4$$$ has divisors $$$[1,2,4]$$$. Thus, there are $$$3$$$ divisors of $$$12$$$ that are not divisors of $$$4$$$ — $$$[3,6,12]$$$.There is no edge between $$$3$$$ and $$$2$$$ because $$$3$$$ is not divisible by $$$2$$$. There is no edge between $$$12$$$ and $$$3$$$ because $$$\frac{12}{3}=4$$$ is not a prime.Let the length of the path between some vertices $$$v$$$ and $$$u$$$ in the graph be the total weight of edges on it. For example, path $$$[(1, 2), (2, 6), (6, 12), (12, 4), (4, 2), (2, 6)]$$$ has length $$$1+2+2+3+1+2=11$$$. The empty path has length $$$0$$$.So the shortest path between two vertices $$$v$$$ and $$$u$$$ is the path that has the minimal possible length.Two paths $$$a$$$ and $$$b$$$ are different if there is either a different number of edges in them or there is a position $$$i$$$ such that $$$a_i$$$ and $$$b_i$$$ are different edges.You are given $$$q$$$ queries of the following form:   $$$v$$$ $$$u$$$ — calculate the number of the shortest paths between vertices $$$v$$$ and $$$u$$$. The answer for each query might be large so print it modulo $$$998244353$$$.","['graphs', 'math', 'number theory']","[0, 0, 1, 1, 1, 0, 0, 0]"477"You have a list of numbers from $$$1$$$ to $$$n$$$ written from left to right on the blackboard.You perform an algorithm consisting of several steps (steps are $$$1$$$-indexed). On the $$$i$$$-th step you wipe the $$$i$$$-th number (considering only remaining numbers). You wipe the whole number (not one digit).  When there are less than $$$i$$$ numbers remaining, you stop your algorithm. Now you wonder: what is the value of the $$$x$$$-th remaining number after the algorithm is stopped?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"478"Country of Metropolia is holding Olympiad of Metrpolises soon. It mean that all jury members of the olympiad should meet together in Metropolis (the capital of the country) for the problem preparation process.There are n + 1 cities consecutively numbered from 0 to n. City 0 is Metropolis that is the meeting point for all jury members. For each city from 1 to n there is exactly one jury member living there. Olympiad preparation is a long and demanding process that requires k days of work. For all of these k days each of the n jury members should be present in Metropolis to be able to work on problems.You know the flight schedule in the country (jury members consider themselves important enough to only use flights for transportation). All flights in Metropolia are either going to Metropolis or out of Metropolis. There are no night flights in Metropolia, or in the other words, plane always takes off at the same day it arrives. On his arrival day and departure day jury member is not able to discuss the olympiad. All flights in Megapolia depart and arrive at the same day.Gather everybody for k days in the capital is a hard objective, doing that while spending the minimum possible money is even harder. Nevertheless, your task is to arrange the cheapest way to bring all of the jury members to Metrpolis, so that they can work together for k days and then send them back to their home cities. Cost of the arrangement is defined as a total cost of tickets for all used flights. It is allowed for jury member to stay in Metropolis for more than k days.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"479"Petya loves lucky numbers. We all know that lucky numbers are the positive integers whose decimal representations contain only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.Petya got an array consisting of n numbers, it is the gift for his birthday. Now he wants to sort it in the non-decreasing order. However, a usual sorting is boring to perform, that's why Petya invented the following limitation: one can swap any two numbers but only if at least one of them is lucky. Your task is to sort the array according to the specified limitation. Find any possible sequence of the swaps (the number of operations in the sequence should not exceed 2n).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"480"You are asked to build an array $$$a$$$, consisting of $$$n$$$ integers, each element should be from $$$1$$$ to $$$k$$$.The array should be non-decreasing ($$$a_i \le a_{i+1}$$$ for all $$$i$$$ from $$$1$$$ to $$$n-1$$$). You are also given additional constraints on it. Each constraint is of one of three following types:   $$$1~i~x$$$: $$$a_i$$$ should not be equal to $$$x$$$;  $$$2~i~j~x$$$: $$$a_i + a_j$$$ should be less than or equal to $$$x$$$;  $$$3~i~j~x$$$: $$$a_i + a_j$$$ should be greater than or equal to $$$x$$$. Build any non-decreasing array that satisfies all constraints or report that no such array exists.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"481Bachgold problem is very easy to formulate. Given a positive integer n represent it as a sum of maximum possible number of prime numbers. One can prove that such representation exists for any integer greater than 1.Recall that integer k is called prime if it is greater than 1 and has exactly two positive integer divisors — 1 and k. ,"['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"482"You are given string s. Your task is to determine if the given string s contains two non-overlapping substrings ""AB"" and ""BA"" (the substrings can go in any order).",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"483"The Travelling Salesman spends a lot of time travelling so he tends to get bored. To pass time, he likes to perform operations on numbers. One such operation is to take a positive integer x and reduce it to the number of bits set to 1 in the binary representation of x. For example for number 13 it's true that 1310 = 11012, so it has 3 bits set and 13 will be reduced to 3 in one operation.He calls a number special if the minimum number of operations to reduce it to 1 is k.He wants to find out how many special numbers exist which are not greater than n. Please help the Travelling Salesman, as he is about to reach his destination!Since the answer can be large, output it modulo 109 + 7.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"484"Recently Polycarp started to develop a text editor that works only with correct bracket sequences (abbreviated as CBS). Note that a bracket sequence is correct if it is possible to get a correct mathematical expression by adding ""+""-s and ""1""-s to it. For example, sequences ""(())()"", ""()"" and ""(()(()))"" are correct, while "")("", ""(()"" and ""(()))("" are not. Each bracket in CBS has a pair. For example, in ""(()(()))"":  1st bracket is paired with 8th,  2d bracket is paired with 3d,  3d bracket is paired with 2d,  4th bracket is paired with 7th,  5th bracket is paired with 6th,  6th bracket is paired with 5th,  7th bracket is paired with 4th,  8th bracket is paired with 1st. Polycarp's editor currently supports only three operations during the use of CBS. The cursor in the editor takes the whole position of one of the brackets (not the position between the brackets!). There are three operations being supported:  «L» — move the cursor one position to the left,  «R» — move the cursor one position to the right,  «D» — delete the bracket in which the cursor is located, delete the bracket it's paired to and all brackets between them (that is, delete a substring between the bracket in which the cursor is located and the one it's paired to). After the operation ""D"" the cursor moves to the nearest bracket to the right (of course, among the non-deleted). If there is no such bracket (that is, the suffix of the CBS was deleted), then the cursor moves to the nearest bracket to the left (of course, among the non-deleted). There are pictures illustrated several usages of operation ""D"" below.  All incorrect operations (shift cursor over the end of CBS, delete the whole CBS, etc.) are not supported by Polycarp's editor.Polycarp is very proud of his development, can you implement the functionality of his editor?",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"485"This is the easy version of the problem. The difference between the versions is that the easy version does not require you to output the numbers of the rods to be removed. You can make hacks only if all versions of the problem are solved.Stitch likes experimenting with different machines with his friend Sparky. Today they built another machine.The main element of this machine are $$$n$$$ rods arranged along one straight line and numbered from $$$1$$$ to $$$n$$$ inclusive. Each of these rods must carry an electric charge quantitatively equal to either $$$1$$$ or $$$-1$$$ (otherwise the machine will not work). Another condition for this machine to work is that the sign-variable sum of the charge on all rods must be zero.More formally, the rods can be represented as an array of $$$n$$$ numbers characterizing the charge: either $$$1$$$ or $$$-1$$$. Then the condition must hold: $$$a_1 - a_2 + a_3 - a_4 + \ldots = 0$$$, or $$$\sum\limits_{i=1}^n (-1)^{i-1} \cdot a_i = 0$$$.Sparky charged all $$$n$$$ rods with an electric current, but unfortunately it happened that the rods were not charged correctly (the sign-variable sum of the charge is not zero). The friends decided to leave only some of the rods in the machine. Sparky has $$$q$$$ questions. In the $$$i$$$th question Sparky asks: if the machine consisted only of rods with numbers $$$l_i$$$ to $$$r_i$$$ inclusive, what minimal number of rods could be removed from the machine so that the sign-variable sum of charges on the remaining ones would be zero? Perhaps the friends got something wrong, and the sign-variable sum is already zero. In that case, you don't have to remove the rods at all.If the number of rods is zero, we will assume that the sign-variable sum of charges is zero, that is, we can always remove all rods.Help your friends and answer all of Sparky's questions!",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"486"Tomash keeps wandering off and getting lost while he is walking along the streets of Berland. It's no surprise! In his home town, for any pair of intersections there is exactly one way to walk from one intersection to the other one. The capital of Berland is very different!Tomash has noticed that even simple cases of ambiguity confuse him. So, when he sees a group of four distinct intersections a, b, c and d, such that there are two paths from a to c — one through b and the other one through d, he calls the group a ""damn rhombus"". Note that pairs (a, b), (b, c), (a, d), (d, c) should be directly connected by the roads. Schematically, a damn rhombus is shown on the figure below:  Other roads between any of the intersections don't make the rhombus any more appealing to Tomash, so the four intersections remain a ""damn rhombus"" for him.Given that the capital of Berland has n intersections and m roads and all roads are unidirectional and are known in advance, find the number of ""damn rhombi"" in the city.When rhombi are compared, the order of intersections b and d doesn't matter.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"487"Recently Polycarpus has learned the ""bitwise AND"" operation (which is also called ""AND"") of non-negative integers. Now he wants to demonstrate the school IT teacher his superb manipulation with the learned operation.For that Polycarpus came to school a little earlier and wrote on the board a sequence of non-negative integers a1, a2, ..., an. He also wrote a square matrix b of size n × n. The element of matrix b that sits in the i-th row in the j-th column (we'll denote it as bij) equals:  the ""bitwise AND"" of numbers ai and aj (that is, bij = ai & aj), if i ≠ j;  -1, if i = j. Having written out matrix b, Polycarpus got very happy and wiped a off the blackboard. But the thing is, the teacher will want this sequence to check whether Polycarpus' calculations were correct. Polycarus urgently needs to restore the removed sequence of integers, or else he won't prove that he can count correctly.Help Polycarpus, given matrix b, restore the sequence of numbers a1, a2, ..., an, that he has removed from the board. Polycarpus doesn't like large numbers, so any number in the restored sequence mustn't exceed 109.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"488"Robot Bender decided to make Fray a birthday present. He drove n nails and numbered them from 1 to n in some order. Bender decided to make a picture using metal rods. The picture is a closed polyline, which vertices should be nails (in the given order). The segments of the polyline should be parallel to the coordinate axes. Polyline is allowed to have self-intersections. Bender can take a rod and fold it exactly once in any place to form an angle of 90 degrees. Then he can attach the place of the fold to some unoccupied nail and attach two ends of this rod to adjacent nails. A nail is considered unoccupied if there is no rod attached to it (neither by it's end nor the by the fold place). No rod could be used twice. It is not required to use all the rods.Help Bender to solve this difficult task.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"489"The only difference between this problem and D1 is the bound on the size of the tree.You are given an unrooted tree with $$$n$$$ vertices. There is some hidden vertex $$$x$$$ in that tree that you are trying to find.To do this, you may ask $$$k$$$ queries $$$v_1, v_2, \ldots, v_k$$$ where the $$$v_i$$$ are vertices in the tree. After you are finished asking all of the queries, you are given $$$k$$$ numbers $$$d_1, d_2, \ldots, d_k$$$, where $$$d_i$$$ is the number of edges on the shortest path between $$$v_i$$$ and $$$x$$$. Note that you know which distance corresponds to which query.What is the minimum $$$k$$$ such that there exists some queries $$$v_1, v_2, \ldots, v_k$$$ that let you always uniquely identify $$$x$$$ (no matter what $$$x$$$ is).Note that you don't actually need to output these queries.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"490"The difference between the versions is in the costs of operations. Solution for one version won't work for another!Alice has a grid of size $$$n \times m$$$, initially all its cells are colored white. The cell on the intersection of $$$i$$$-th row and $$$j$$$-th column is denoted as $$$(i, j)$$$. Alice can do the following operations with this grid:Choose any subrectangle containing cell $$$(1, 1)$$$, and flip the colors of all its cells. (Flipping means changing its color from white to black or from black to white). This operation costs $$$1$$$ coin.Choose any subrectangle containing cell $$$(n, 1)$$$, and flip the colors of all its cells. This operation costs $$$3$$$ coins.Choose any subrectangle containing cell $$$(1, m)$$$, and flip the colors of all its cells. This operation costs $$$4$$$ coins.Choose any subrectangle containing cell $$$(n, m)$$$, and flip the colors of all its cells. This operation costs $$$2$$$ coins. As a reminder, subrectangle is a set of all cells $$$(x, y)$$$ with $$$x_1 \le x \le x_2$$$, $$$y_1 \le y \le y_2$$$ for some $$$1 \le x_1 \le x_2 \le n$$$, $$$1 \le y_1 \le y_2 \le m$$$.Alice wants to obtain her favorite coloring with these operations. What's the smallest number of coins that she would have to spend? It can be shown that it's always possible to transform the initial grid into any other.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"491"Devu being a small kid, likes to play a lot, but he only likes to play with arrays. While playing he came up with an interesting question which he could not solve, can you please solve it for him?Given an array consisting of distinct integers. Is it possible to partition the whole array into k disjoint non-empty parts such that p of the parts have even sum (each of them must have even sum) and remaining k - p have odd sum? (note that parts need not to be continuous).If it is possible to partition the array, also give any possible way of valid partitioning.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"492"You are standing at the point $$$0$$$ on a coordinate line. Your goal is to reach the point $$$n$$$. In one minute, you can move by $$$2$$$ or by $$$3$$$ to the left or to the right (i. e., if your current coordinate is $$$x$$$, it can become $$$x-3$$$, $$$x-2$$$, $$$x+2$$$ or $$$x+3$$$). Note that the new coordinate can become negative.Your task is to find the minimum number of minutes required to get from the point $$$0$$$ to the point $$$n$$$.You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"493"Toad Pimple has an array of integers $$$a_1, a_2, \ldots, a_n$$$.We say that $$$y$$$ is reachable from $$$x$$$ if $$$x<y$$$ and there exists an integer array $$$p$$$ such that $$$x = p_1 < p_2 < \ldots < p_k=y$$$, and $$$a_{p_i}\, \&\, a_{p_{i+1}} > 0$$$ for all integers $$$i$$$ such that $$$1 \leq i < k$$$.Here $$$\&$$$ denotes the bitwise AND operation.You are given $$$q$$$ pairs of indices, check reachability for each of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"494"Leo Jr. draws pictures in his notebook with checkered sheets (that is, each sheet has a regular square grid printed on it). We can assume that the sheets are infinitely large in any direction.To draw a picture, Leo Jr. colors some of the cells on a sheet gray. He considers the resulting picture beautiful if the following conditions are satisfied: The picture is connected, that is, it is possible to get from any gray cell to any other by following a chain of gray cells, with each pair of adjacent cells in the path being neighbours (that is, sharing a side). Each gray cell has an even number of gray neighbours. There are exactly $$$n$$$ gray cells with all gray neighbours. The number of other gray cells can be arbitrary (but reasonable, so that they can all be listed).Leo Jr. is now struggling to draw a beautiful picture with a particular choice of $$$n$$$. Help him, and provide any example of a beautiful picture.To output cell coordinates in your answer, assume that the sheet is provided with a Cartesian coordinate system such that one of the cells is chosen to be the origin $$$(0, 0)$$$, axes $$$0x$$$ and $$$0y$$$ are orthogonal and parallel to grid lines, and a unit step along any axis in any direction takes you to a neighbouring cell.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"495"Little Mishka is a great traveller and she visited many countries. After thinking about where to travel this time, she chose XXX — beautiful, but little-known northern country.Here are some interesting facts about XXX:  XXX consists of n cities, k of whose (just imagine!) are capital cities.  All of cities in the country are beautiful, but each is beautiful in its own way. Beauty value of i-th city equals to ci.  All the cities are consecutively connected by the roads, including 1-st and n-th city, forming a cyclic route 1 — 2 — ... — n — 1. Formally, for every 1 ≤ i < n there is a road between i-th and i + 1-th city, and another one between 1-st and n-th city.  Each capital city is connected with each other city directly by the roads. Formally, if city x is a capital city, then for every 1 ≤ i ≤ n,  i ≠ x, there is a road between cities x and i.  There is at most one road between any two cities.  Price of passing a road directly depends on beauty values of cities it connects. Thus if there is a road between cities i and j, price of passing it equals ci·cj.Mishka started to gather her things for a trip, but didn't still decide which route to follow and thus she asked you to help her determine summary price of passing each of the roads in XXX. Formally, for every pair of cities a and b (a < b), such that there is a road between a and b you are to find sum of products ca·cb. Will you help her?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"496"Many countries have such a New Year or Christmas tradition as writing a letter to Santa including a wish list for presents. Vasya is an ordinary programmer boy. Like all ordinary boys, he is going to write the letter to Santa on the New Year Eve (we Russians actually expect Santa for the New Year, not for Christmas). Vasya has come up with an algorithm he will follow while writing a letter. First he chooses two strings, s1 anf s2, consisting of uppercase English letters. Then the boy makes string sk, using a recurrent equation sn = sn - 2 + sn - 1, operation '+' means a concatenation (that is, the sequential record) of strings in the given order. Then Vasya writes down string sk on a piece of paper, puts it in the envelope and sends in to Santa. Vasya is absolutely sure that Santa will bring him the best present if the resulting string sk has exactly x occurrences of substring AC (the short-cut reminds him оf accepted problems). Besides, Vasya decided that string s1 should have length n, and string s2 should have length m. Vasya hasn't decided anything else.At the moment Vasya's got urgent New Year business, so he asks you to choose two strings for him, s1 and s2 in the required manner. Help Vasya.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"497"A subway scheme, classic for all Berland cities is represented by a set of n stations connected by n passages, each of which connects exactly two stations and does not pass through any others. Besides, in the classic scheme one can get from any station to any other one along the passages. The passages can be used to move in both directions. Between each pair of stations there is no more than one passage.Berland mathematicians have recently proved a theorem that states that any classic scheme has a ringroad. There can be only one ringroad. In other words, in any classic scheme one can find the only scheme consisting of stations (where any two neighbouring ones are linked by a passage) and this cycle doesn't contain any station more than once.This invention had a powerful social impact as now the stations could be compared according to their distance from the ringroad. For example, a citizen could say ""I live in three passages from the ringroad"" and another one could reply ""you loser, I live in one passage from the ringroad"". The Internet soon got filled with applications that promised to count the distance from the station to the ringroad (send a text message to a short number...).The Berland government decided to put an end to these disturbances and start to control the situation. You are requested to write a program that can determine the remoteness from the ringroad for each station by the city subway scheme.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"498"Polycarp has just attempted to pass the driving test. He ran over the straight road with the signs of four types.  speed limit: this sign comes with a positive integer number — maximal speed of the car after the sign (cancel the action of the previous sign of this type);  overtake is allowed: this sign means that after some car meets it, it can overtake any other car;  no speed limit: this sign cancels speed limit if any (car can move with arbitrary speed after this sign);  no overtake allowed: some car can't overtake any other car after this sign. Polycarp goes past the signs consequentially, each new sign cancels the action of all the previous signs of it's kind (speed limit/overtake). It is possible that two or more ""no overtake allowed"" signs go one after another with zero ""overtake is allowed"" signs between them. It works with ""no speed limit"" and ""overtake is allowed"" signs as well.In the beginning of the ride overtake is allowed and there is no speed limit.You are given the sequence of events in chronological order — events which happened to Polycarp during the ride. There are events of following types:  Polycarp changes the speed of his car to specified (this event comes with a positive integer number);  Polycarp's car overtakes the other car;  Polycarp's car goes past the ""speed limit"" sign (this sign comes with a positive integer);  Polycarp's car goes past the ""overtake is allowed"" sign;  Polycarp's car goes past the ""no speed limit"";  Polycarp's car goes past the ""no overtake allowed""; It is guaranteed that the first event in chronological order is the event of type 1 (Polycarp changed the speed of his car to specified).After the exam Polycarp can justify his rule violations by telling the driving instructor that he just didn't notice some of the signs. What is the minimal number of signs Polycarp should say he didn't notice, so that he would make no rule violations from his point of view?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"499"Fillomino is a classic logic puzzle. (You do not need to know Fillomino in order to solve this problem.) In one classroom in Yunqi town, some volunteers are playing a board game variant of it:Consider an $$$n$$$ by $$$n$$$ chessboard. Its rows are numbered from $$$1$$$ to $$$n$$$ from the top to the bottom. Its columns are numbered from $$$1$$$ to $$$n$$$ from the left to the right. A cell on an intersection of $$$x$$$-th row and $$$y$$$-th column is denoted $$$(x, y)$$$. The main diagonal of the chessboard is cells $$$(x, x)$$$ for all $$$1 \le x \le n$$$.A permutation of $$$\{1, 2, 3, \dots, n\}$$$ is written on the main diagonal of the chessboard. There is exactly one number written on each of the cells. The problem is to partition the cells under and on the main diagonal (there are exactly $$$1+2+ \ldots +n$$$ such cells) into $$$n$$$ connected regions satisfying the following constraints:  Every region should be connected. That means that we can move from any cell of a region to any other cell of the same region visiting only cells of the same region and moving from a cell to an adjacent cell.  The $$$x$$$-th region should contain cell on the main diagonal with number $$$x$$$ for all $$$1\le x\le n$$$.  The number of cells that belong to the $$$x$$$-th region should be equal to $$$x$$$ for all $$$1\le x\le n$$$.  Each cell under and on the main diagonal should belong to exactly one region. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"500"You have a string $$$s$$$ — a sequence of commands for your toy robot. The robot is placed in some cell of a rectangular grid. He can perform four commands:  'W' — move one cell up;  'S' — move one cell down;  'A' — move one cell left;  'D' — move one cell right. Let $$$Grid(s)$$$ be the grid of minimum possible area such that there is a position in the grid where you can place the robot in such a way that it will not fall from the grid while running the sequence of commands $$$s$$$. For example, if $$$s = \text{DSAWWAW}$$$ then $$$Grid(s)$$$ is the $$$4 \times 3$$$ grid:  you can place the robot in the cell $$$(3, 2)$$$;  the robot performs the command 'D' and moves to $$$(3, 3)$$$;  the robot performs the command 'S' and moves to $$$(4, 3)$$$;  the robot performs the command 'A' and moves to $$$(4, 2)$$$;  the robot performs the command 'W' and moves to $$$(3, 2)$$$;  the robot performs the command 'W' and moves to $$$(2, 2)$$$;  the robot performs the command 'A' and moves to $$$(2, 1)$$$;  the robot performs the command 'W' and moves to $$$(1, 1)$$$.   You have $$$4$$$ extra letters: one 'W', one 'A', one 'S', one 'D'. You'd like to insert at most one of these letters in any position of sequence $$$s$$$ to minimize the area of $$$Grid(s)$$$.What is the minimum area of $$$Grid(s)$$$ you can achieve?","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"501"Graph constructive problems are back! This time the graph you are asked to build should match the following properties.The graph is connected if and only if there exists a path between every pair of vertices.The diameter (aka ""longest shortest path"") of a connected undirected graph is the maximum number of edges in the shortest path between any pair of its vertices.The degree of a vertex is the number of edges incident to it.Given a sequence of $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$ construct a connected undirected graph of $$$n$$$ vertices such that:  the graph contains no self-loops and no multiple edges;  the degree $$$d_i$$$ of the $$$i$$$-th vertex doesn't exceed $$$a_i$$$ (i.e. $$$d_i \le a_i$$$);  the diameter of the graph is maximum possible. Output the resulting graph or report that no solution exists.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"502"You have an array $$$a$$$ of length $$$n$$$. You can exactly once select an integer $$$len$$$ between $$$1$$$ and $$$n - 1$$$ inclusively, and then sort in non-decreasing order the prefix of the array of length $$$len$$$ and the suffix of the array of length $$$n - len$$$ independently.For example, if the array is $$$a = [3, 1, 4, 5, 2]$$$, and you choose $$$len = 2$$$, then after that the array will be equal to $$$[1, 3, 2, 4, 5]$$$.Could it be that after performing this operation, the array will not be sorted in non-decreasing order?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"503"There is a famous olympiad, which has more than a hundred participants. The Olympiad consists of two stages: the elimination stage, and the final stage. At least a hundred participants will advance to the final stage. The elimination stage in turn consists of two contests.A result of the elimination stage is the total score in two contests, but, unfortunately, the jury lost the final standings and has only standings for the first and for the second contest separately. In each contest, the participants are ranked by their point score in non-increasing order. When two participants have a tie (earned the same score), they are ranked by their passport number (in accordance with local regulations, all passport numbers are distinct). In the first contest, the participant on the 100-th place scored $$$a$$$ points. Also, the jury checked all participants from the 1-st to the 100-th place (inclusive) in the first contest and found out that all of them have at least $$$b$$$ points in the second contest.Similarly, for the second contest, the participant on the 100-th place has $$$c$$$ points. And the jury checked that all the participants from the 1-st to the 100-th place (inclusive) have at least $$$d$$$ points in the first contest.After two contests, all participants are ranked by their total score in two contests in non-increasing order. When participants have the same total score, tie-breaking with passport numbers is used. The cutoff score to qualify to the final stage is the total score of the participant on the 100-th place.Given integers $$$a$$$, $$$b$$$, $$$c$$$, $$$d$$$, please help the jury determine the smallest possible value of the cutoff score.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"504"You are given an array $$$a_1, a_2, \dots , a_n$$$, which is sorted in non-decreasing order ($$$a_i \le a_{i + 1})$$$. Find three indices $$$i$$$, $$$j$$$, $$$k$$$ such that $$$1 \le i < j < k \le n$$$ and it is impossible to construct a non-degenerate triangle (a triangle with nonzero area) having sides equal to $$$a_i$$$, $$$a_j$$$ and $$$a_k$$$ (for example it is possible to construct a non-degenerate triangle with sides $$$3$$$, $$$4$$$ and $$$5$$$ but impossible with sides $$$3$$$, $$$4$$$ and $$$7$$$). If it is impossible to find such triple, report it.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"505"Let's consider a k × k square, divided into unit squares. Please note that k ≥ 3 and is odd. We'll paint squares starting from the upper left square in the following order: first we move to the right, then down, then to the left, then up, then to the right again and so on. We finish moving in some direction in one of two cases: either we've reached the square's border or the square following after the next square is already painted. We finish painting at the moment when we cannot move in any direction and paint a square. The figure that consists of the painted squares is a spiral.   The figure shows examples of spirals for k = 3, 5, 7, 9.  You have an n × m table, each of its cells contains a number. Let's consider all possible spirals, formed by the table cells. It means that we consider all spirals of any size that don't go beyond the borders of the table. Let's find the sum of the numbers of the cells that form the spiral. You have to find the maximum of those values among all spirals.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"506"Sakuzyo - ImprintingA.R.C. Markland-N is a tall building with $$$n$$$ floors numbered from $$$1$$$ to $$$n$$$. Between each two adjacent floors in the building, there is a staircase connecting them.It's lunchtime for our sensei Colin ""ConneR"" Neumann Jr, and he's planning for a location to enjoy his meal.ConneR's office is at floor $$$s$$$ of the building. On each floor (including floor $$$s$$$, of course), there is a restaurant offering meals. However, due to renovations being in progress, $$$k$$$ of the restaurants are currently closed, and as a result, ConneR can't enjoy his lunch there.CooneR wants to reach a restaurant as quickly as possible to save time. What is the minimum number of staircases he needs to walk to reach a closest currently open restaurant.Please answer him quickly, and you might earn his praise and even enjoy the lunch with him in the elegant Neumanns' way!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"507"Olya likes milk very much. She drinks k cartons of milk each day if she has at least k and drinks all of them if she doesn't. But there's an issue — expiration dates. Each carton has a date after which you can't drink it (you still can drink it exactly at the date written on the carton). Due to this, if Olya's fridge contains a carton past its expiry date, she throws it away.Olya hates throwing out cartons, so when she drinks a carton, she chooses the one which expires the fastest. It's easy to understand that this strategy minimizes the amount of cartons thrown out and lets her avoid it if it's even possible.    Milk. Best before: 20.02.2017. The main issue Olya has is the one of buying new cartons. Currently, there are n cartons of milk in Olya's fridge, for each one an expiration date is known (how soon does it expire, measured in days). In the shop that Olya visited there are m cartons, and the expiration date is known for each of those cartons as well.Find the maximum number of cartons Olya can buy so that she wouldn't have to throw away any cartons. Assume that Olya drank no cartons today. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"508"The bear has a string s = s1s2... s|s| (record |s| is the string's length), consisting of lowercase English letters. The bear wants to count the number of such pairs of indices i, j (1 ≤ i ≤ j ≤ |s|), that string x(i, j) = sisi + 1... sj contains at least one string ""bear"" as a substring.String x(i, j) contains string ""bear"", if there is such index k (i ≤ k ≤ j - 3), that sk = b, sk + 1 = e, sk + 2 = a, sk + 3 = r.Help the bear cope with the given problem.","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"509"Tanya wants to go on a journey across the cities of Berland. There are $$$n$$$ cities situated along the main railroad line of Berland, and these cities are numbered from $$$1$$$ to $$$n$$$. Tanya plans her journey as follows. First of all, she will choose some city $$$c_1$$$ to start her journey. She will visit it, and after that go to some other city $$$c_2 > c_1$$$, then to some other city $$$c_3 > c_2$$$, and so on, until she chooses to end her journey in some city $$$c_k > c_{k - 1}$$$. So, the sequence of visited cities $$$[c_1, c_2, \dots, c_k]$$$ should be strictly increasing.There are some additional constraints on the sequence of cities Tanya visits. Each city $$$i$$$ has a beauty value $$$b_i$$$ associated with it. If there is only one city in Tanya's journey, these beauty values imply no additional constraints. But if there are multiple cities in the sequence, then for any pair of adjacent cities $$$c_i$$$ and $$$c_{i + 1}$$$, the condition $$$c_{i + 1} - c_i = b_{c_{i + 1}} - b_{c_i}$$$ must hold.For example, if $$$n = 8$$$ and $$$b = [3, 4, 4, 6, 6, 7, 8, 9]$$$, there are several three possible ways to plan a journey:  $$$c = [1, 2, 4]$$$;  $$$c = [3, 5, 6, 8]$$$;  $$$c = [7]$$$ (a journey consisting of one city is also valid). There are some additional ways to plan a journey that are not listed above.Tanya wants her journey to be as beautiful as possible. The beauty value of the whole journey is the sum of beauty values over all visited cities. Can you help her to choose the optimal plan, that is, to maximize the beauty value of the journey?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"510"The process of mammoth's genome decoding in Berland comes to its end!One of the few remaining tasks is to restore unrecognized nucleotides in a found chain s. Each nucleotide is coded with a capital letter of English alphabet: 'A', 'C', 'G' or 'T'. Unrecognized nucleotides are coded by a question mark '?'. Thus, s is a string consisting of letters 'A', 'C', 'G', 'T' and characters '?'.It is known that the number of nucleotides of each of the four types in the decoded genome of mammoth in Berland should be equal.Your task is to decode the genome and replace each unrecognized nucleotide with one of the four types so that the number of nucleotides of each of the four types becomes equal.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"511"In the year of $$$30XX$$$ participants of some world programming championship live in a single large hotel. The hotel has $$$n$$$ floors. Each floor has $$$m$$$ sections with a single corridor connecting all of them. The sections are enumerated from $$$1$$$ to $$$m$$$ along the corridor, and all sections with equal numbers on different floors are located exactly one above the other. Thus, the hotel can be represented as a rectangle of height $$$n$$$ and width $$$m$$$. We can denote sections with pairs of integers $$$(i, j)$$$, where $$$i$$$ is the floor, and $$$j$$$ is the section number on the floor.The guests can walk along the corridor on each floor, use stairs and elevators. Each stairs or elevator occupies all sections $$$(1, x)$$$, $$$(2, x)$$$, $$$\ldots$$$, $$$(n, x)$$$ for some $$$x$$$ between $$$1$$$ and $$$m$$$. All sections not occupied with stairs or elevators contain guest rooms. It takes one time unit to move between neighboring sections on the same floor or to move one floor up or down using stairs. It takes one time unit to move up to $$$v$$$ floors in any direction using an elevator. You can assume you don't have to wait for an elevator, and the time needed to enter or exit an elevator is negligible.You are to process $$$q$$$ queries. Each query is a question ""what is the minimum time needed to go from a room in section $$$(x_1, y_1)$$$ to a room in section $$$(x_2, y_2)$$$?""",[],"[0, 0, 0, 0, 0, 0, 0, 0]"512"You are fighting with Zmei Gorynich — a ferocious monster from Slavic myths, a huge dragon-like reptile with multiple heads!   Initially Zmei Gorynich has $$$x$$$ heads. You can deal $$$n$$$ types of blows. If you deal a blow of the $$$i$$$-th type, you decrease the number of Gorynich's heads by $$$min(d_i, curX)$$$, there $$$curX$$$ is the current number of heads. But if after this blow Zmei Gorynich has at least one head, he grows $$$h_i$$$ new heads. If $$$curX = 0$$$ then Gorynich is defeated. You can deal each blow any number of times, in any order.For example, if $$$curX = 10$$$, $$$d = 7$$$, $$$h = 10$$$ then the number of heads changes to $$$13$$$ (you cut $$$7$$$ heads off, but then Zmei grows $$$10$$$ new ones), but if $$$curX = 10$$$, $$$d = 11$$$, $$$h = 100$$$ then number of heads changes to $$$0$$$ and Zmei Gorynich is considered defeated.Calculate the minimum number of blows to defeat Zmei Gorynich!You have to answer $$$t$$$ independent queries.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"513"In Chelyabinsk lives a much respected businessman Nikita with a strange nickname ""Boss"". Once Nikita decided to go with his friend Alex to the Summer Biathlon World Cup. Nikita, as a very important person, received a token which allows to place bets on each section no more than on one competitor.To begin with friends learned the rules: in the race there are n sections of equal length and m participants. The participants numbered from 1 to m. About each participant the following is known: li — the number of the starting section,  ri — the number of the finishing section (li ≤ ri), ti — the time a biathlete needs to complete an section of the path, ci — the profit in roubles. If the i-th sportsman wins on one of the sections, the profit will be given to the man who had placed a bet on that sportsman. The i-th biathlete passes the sections from li to ri inclusive. The competitor runs the whole way in (ri - li + 1)·ti time units. It takes him exactly ti time units to pass each section. In case of the athlete's victory on k sections the man who has betted on him receives k·ci roubles.In each section the winner is determined independently as follows: if there is at least one biathlete running this in this section, then among all of them the winner is the one who has ran this section in minimum time (spent minimum time passing this section). In case of equality of times the athlete with the smaller index number wins. If there are no participants in this section, then the winner in this section in not determined. We have to say that in the summer biathlon all the participants are moving at a constant speed.We should also add that Nikita can bet on each section and on any contestant running in this section.Help the friends find the maximum possible profit.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"514"The city administration of IT City decided to fix up a symbol of scientific and technical progress in the city's main square, namely an indicator board that shows the effect of Moore's law in real time.Moore's law is the observation that the number of transistors in a dense integrated circuit doubles approximately every 24 months. The implication of Moore's law is that computer performance as function of time increases exponentially as well.You are to prepare information that will change every second to display on the indicator board. Let's assume that every second the number of transistors increases exactly 1.000000011 times.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"515"It is a holiday season, and Koala is decorating his house with cool lights! He owns $$$n$$$ lights, all of which flash periodically.After taking a quick glance at them, Koala realizes that each of his lights can be described with two parameters $$$a_i$$$ and $$$b_i$$$. Light with parameters $$$a_i$$$ and $$$b_i$$$ will toggle (on to off, or off to on) every $$$a_i$$$ seconds starting from the $$$b_i$$$-th second. In other words, it will toggle at the moments $$$b_i$$$, $$$b_i + a_i$$$, $$$b_i + 2 \cdot a_i$$$ and so on.You know for each light whether it's initially on or off and its corresponding parameters $$$a_i$$$ and $$$b_i$$$. Koala is wondering what is the maximum number of lights that will ever be on at the same time. So you need to find that out.    Here is a graphic for the first example. ","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"516"Mihai has just learned about the MEX concept and since he liked it so much, he decided to use it right away.Given an array $$$a$$$ of $$$n$$$ non-negative integers, Mihai wants to create a new array $$$b$$$ that is formed in the following way:While $$$a$$$ is not empty:   Choose an integer $$$k$$$ ($$$1 \leq k \leq |a|$$$).  Append the MEX of the first $$$k$$$ numbers of the array $$$a$$$ to the end of array $$$b$$$ and erase them from the array $$$a$$$, shifting the positions of the remaining numbers in $$$a$$$. But, since Mihai loves big arrays as much as the MEX concept, he wants the new array $$$b$$$ to be the lexicographically maximum. So, Mihai asks you to tell him what the maximum array $$$b$$$ that can be created by constructing the array optimally is.An array $$$x$$$ is lexicographically greater than an array $$$y$$$ if in the first position where $$$x$$$ and $$$y$$$ differ $$$x_i > y_i$$$ or if $$$|x| > |y|$$$ and $$$y$$$ is a prefix of $$$x$$$ (where $$$|x|$$$ denotes the size of the array $$$x$$$).The MEX of a set of non-negative integers is the minimal non-negative integer such that it is not in the set. For example, MEX({$$${1, 2, 3}$$$}) $$$= 0$$$ and MEX({$$${0, 1, 2, 4, 5}$$$}) $$$= 3$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"517"""We've tried solitary confinement, waterboarding and listening to Just In Beaver, to no avail. We need something extreme.""""Little Alena got an array as a birthday present...""The array b of length n is obtained from the array a of length n and two integers l and r (l ≤ r) using the following procedure:b1 = b2 = b3 = b4 = 0.For all 5 ≤ i ≤ n:   bi = 0 if ai, ai - 1, ai - 2, ai - 3, ai - 4 > r and bi - 1 = bi - 2 = bi - 3 = bi - 4 = 1  bi = 1 if ai, ai - 1, ai - 2, ai - 3, ai - 4 < l and bi - 1 = bi - 2 = bi - 3 = bi - 4 = 0  bi = bi - 1 otherwise You are given arrays a and b' of the same length. Find two integers l and r (l ≤ r), such that applying the algorithm described above will yield an array b equal to b'.It's guaranteed that the answer exists.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"518"The Government of Mars is not only interested in optimizing space flights, but also wants to improve the road system of the planet.One of the most important highways of Mars connects Olymp City and Kstolop, the capital of Cydonia. In this problem, we only consider the way from Kstolop to Olymp City, but not the reverse path (i. e. the path from Olymp City to Kstolop).The road from Kstolop to Olymp City is $$$\ell$$$ kilometers long. Each point of the road has a coordinate $$$x$$$ ($$$0 \le x \le \ell$$$), which is equal to the distance from Kstolop in kilometers. So, Kstolop is located in the point with coordinate $$$0$$$, and Olymp City is located in the point with coordinate $$$\ell$$$.There are $$$n$$$ signs along the road, $$$i$$$-th of which sets a speed limit $$$a_i$$$. This limit means that the next kilometer must be passed in $$$a_i$$$ minutes and is active until you encounter the next along the road. There is a road sign at the start of the road (i. e. in the point with coordinate $$$0$$$), which sets the initial speed limit.If you know the location of all the signs, it's not hard to calculate how much time it takes to drive from Kstolop to Olymp City. Consider an example:  Here, you need to drive the first three kilometers in five minutes each, then one kilometer in eight minutes, then four kilometers in three minutes each, and finally the last two kilometers must be passed in six minutes each. Total time is $$$3\cdot 5 + 1\cdot 8 + 4\cdot 3 + 2\cdot 6 = 47$$$ minutes.To optimize the road traffic, the Government of Mars decided to remove no more than $$$k$$$ road signs. It cannot remove the sign at the start of the road, otherwise, there will be no limit at the start. By removing these signs, the Government also wants to make the time needed to drive from Kstolop to Olymp City as small as possible.The largest industrial enterprises are located in Cydonia, so it's the priority task to optimize the road traffic from Olymp City. So, the Government of Mars wants you to remove the signs in the way described above.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"519"Luke likes to eat. There are $$$n$$$ piles of food aligned in a straight line in front of him. The $$$i$$$-th pile contains $$$a_i$$$ units of food. Luke will walk from the $$$1$$$-st pile towards the $$$n$$$-th pile, and he wants to eat every pile of food without walking back. When Luke reaches the $$$i$$$-th pile, he can eat that pile if and only if $$$|v - a_i| \leq x$$$, where $$$x$$$ is a fixed integer, and $$$v$$$ is Luke's food affinity.Before Luke starts to walk, he can set $$$v$$$ to any integer. Also, for each $$$i$$$ ($$$1 \leq i \leq n$$$), Luke can change his food affinity to any integer before he eats the $$$i$$$-th pile.Find the minimum number of changes needed to eat every pile of food.Note that the initial choice for $$$v$$$ is not considered as a change.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"520"The All-Berland Team Programming Contest will take place very soon. This year, teams of four are allowed to participate.There are $$$a$$$ programmers and $$$b$$$ mathematicians at Berland State University. How many maximum teams can be made if:  each team must consist of exactly $$$4$$$ students,  teams of $$$4$$$ mathematicians or $$$4$$$ programmers are unlikely to perform well, so the decision was made not to compose such teams. Thus, each team must have at least one programmer and at least one mathematician.Print the required maximum number of teams. Each person can be a member of no more than one team.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"521"Scrooge McDuck keeps his most treasured savings in a home safe with a combination lock. Each time he wants to put there the treasures that he's earned fair and square, he has to open the lock.  The combination lock is represented by n rotating disks with digits from 0 to 9 written on them. Scrooge McDuck has to turn some disks so that the combination of digits on the disks forms a secret combination. In one move, he can rotate one disk one digit forwards or backwards. In particular, in one move he can go from digit 0 to digit 9 and vice versa. What minimum number of actions does he need for that?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"522"This is an interactive problem.Jury initially had a sequence $$$a$$$ of length $$$n$$$, such that $$$a_i = i$$$.The jury chose three integers $$$i$$$, $$$j$$$, $$$k$$$, such that $$$1 \leq i < j < k \leq n$$$, $$$j - i > 1$$$. After that, Jury reversed subsegments $$$[i, j - 1]$$$ and $$$[j, k]$$$ of the sequence $$$a$$$.Reversing a subsegment $$$[l, r]$$$ of the sequence $$$a$$$ means reversing the order of elements $$$a_l, a_{l+1}, \ldots, a_r$$$ in the sequence, i. e. $$$a_l$$$ is swapped with $$$a_r$$$, $$$a_{l+1}$$$ is swapped with $$$a_{r-1}$$$, etc.You are given the number $$$n$$$ and you should find $$$i$$$, $$$j$$$, $$$k$$$ after asking some questions.In one question you can choose two integers $$$l$$$ and $$$r$$$ ($$$1 \leq l \leq r \leq n$$$) and ask the number of inversions on the subsegment $$$[l, r]$$$ of the sequence $$$a$$$. You will be given the number of pairs $$$(i, j)$$$ such that $$$l \leq i < j \leq r$$$, and $$$a_i > a_j$$$.Find the chosen numbers $$$i$$$, $$$j$$$, $$$k$$$ after at most $$$40$$$ questions.The numbers $$$i$$$, $$$j$$$, and $$$k$$$ are fixed before the start of your program and do not depend on your queries.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"523"Hamed has recently found a string t and suddenly became quite fond of it. He spent several days trying to find all occurrences of t in other strings he had. Finally he became tired and started thinking about the following problem. Given a string s how many ways are there to extract k ≥ 1 non-overlapping substrings from it such that each of them contains string t as a substring? More formally, you need to calculate the number of ways to choose two sequences a1, a2, ..., ak and b1, b2, ..., bk satisfying the following requirements:  k ≥ 1          t is a substring of string saisai + 1... sbi (string s is considered as 1-indexed). As the number of ways can be rather large print it modulo 109 + 7.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"524" Denis was very sad after Nastya rejected him. So he decided to walk through the gateways to have some fun. And luck smiled at him! When he entered the first courtyard, he met a strange man who was selling something. Denis bought a mysterious item and it was... Random permutation generator! Denis could not believed his luck.When he arrived home, he began to study how his generator works and learned the algorithm. The process of generating a permutation consists of $$$n$$$ steps. At the $$$i$$$-th step, a place is chosen for the number $$$i$$$ $$$(1 \leq i \leq n)$$$. The position for the number $$$i$$$ is defined as follows:  For all $$$j$$$ from $$$1$$$ to $$$n$$$, we calculate $$$r_j$$$  — the minimum index such that $$$j \leq r_j \leq n$$$, and the position $$$r_j$$$ is not yet occupied in the permutation. If there are no such positions, then we assume that the value of $$$r_j$$$ is not defined.  For all $$$t$$$ from $$$1$$$ to $$$n$$$, we calculate $$$count_t$$$  — the number of positions $$$1 \leq j \leq n$$$ such that $$$r_j$$$ is defined and $$$r_j = t$$$.  Consider the positions that are still not occupied by permutation and among those we consider the positions for which the value in the $$$count$$$ array is maximum.  The generator selects one of these positions for the number $$$i$$$. The generator can choose any position. Let's have a look at the operation of the algorithm in the following example:  Let $$$n = 5$$$ and the algorithm has already arranged the numbers $$$1, 2, 3$$$ in the permutation. Consider how the generator will choose a position for the number $$$4$$$:  The values of $$$r$$$ will be $$$r = [3, 3, 3, 4, \times]$$$, where $$$\times$$$ means an indefinite value.  Then the $$$count$$$ values will be $$$count = [0, 0, 3, 1, 0]$$$.  There are only two unoccupied positions in the permutation: $$$3$$$ and $$$4$$$. The value in the $$$count$$$ array for position $$$3$$$ is $$$3$$$, for position $$$4$$$ it is $$$1$$$.  The maximum value is reached only for position $$$3$$$, so the algorithm will uniquely select this position for number $$$4$$$. Satisfied with his purchase, Denis went home. For several days without a break, he generated permutations. He believes that he can come up with random permutations no worse than a generator. After that, he wrote out the first permutation that came to mind $$$p_1, p_2, \ldots, p_n$$$ and decided to find out if it could be obtained as a result of the generator.Unfortunately, this task was too difficult for him, and he asked you for help. It is necessary to define whether the written permutation could be obtained using the described algorithm if the generator always selects the position Denis needs.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"525"After a long day, Alice and Bob decided to play a little game. The game board consists of $$$n$$$ cells in a straight line, numbered from $$$1$$$ to $$$n$$$, where each cell contains a number $$$a_i$$$ between $$$1$$$ and $$$n$$$. Furthermore, no two cells contain the same number. A token is placed in one of the cells. They take alternating turns of moving the token around the board, with Alice moving first. The current player can move from cell $$$i$$$ to cell $$$j$$$ only if the following two conditions are satisfied:   the number in the new cell $$$j$$$ must be strictly larger than the number in the old cell $$$i$$$ (i.e. $$$a_j > a_i$$$), and  the distance that the token travels during this turn must be a multiple of the number in the old cell (i.e. $$$|i-j|\bmod a_i = 0$$$). Whoever is unable to make a move, loses. For each possible starting position, determine who wins if they both play optimally. It can be shown that the game is always finite, i.e. there always is a winning strategy for one of the players.",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"526"You are given a string $$$s$$$, consisting only of characters '0' or '1'. Let $$$|s|$$$ be the length of $$$s$$$.You are asked to choose some integer $$$k$$$ ($$$k > 0$$$) and find a sequence $$$a$$$ of length $$$k$$$ such that:   $$$1 \le a_1 < a_2 < \dots < a_k \le |s|$$$;  $$$a_{i-1} + 1 < a_i$$$ for all $$$i$$$ from $$$2$$$ to $$$k$$$. The characters at positions $$$a_1, a_2, \dots, a_k$$$ are removed, the remaining characters are concatenated without changing the order. So, in other words, the positions in the sequence $$$a$$$ should not be adjacent.Let the resulting string be $$$s'$$$. $$$s'$$$ is called sorted if for all $$$i$$$ from $$$2$$$ to $$$|s'|$$$ $$$s'_{i-1} \le s'_i$$$.Does there exist such a sequence $$$a$$$ that the resulting string $$$s'$$$ is sorted?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"527"Reminder: the median of the array $$$[a_1, a_2, \dots, a_{2k+1}]$$$ of odd number of elements is defined as follows: let $$$[b_1, b_2, \dots, b_{2k+1}]$$$ be the elements of the array in the sorted order. Then median of this array is equal to $$$b_{k+1}$$$.There are $$$2n$$$ students, the $$$i$$$-th student has skill level $$$a_i$$$. It's not guaranteed that all skill levels are distinct.Let's define skill level of a class as the median of skill levels of students of the class.As a principal of the school, you would like to assign each student to one of the $$$2$$$ classes such that each class has odd number of students (not divisible by $$$2$$$). The number of students in the classes may be equal or different, by your choice. Every student has to be assigned to exactly one class. Among such partitions, you want to choose one in which the absolute difference between skill levels of the classes is minimized.What is the minimum possible absolute difference you can achieve?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"528"In 2013, the writers of Berland State University should prepare problems for n Olympiads. We will assume that the Olympiads are numbered with consecutive integers from 1 to n. For each Olympiad we know how many members of the jury must be involved in its preparation, as well as the time required to prepare the problems for her. Namely, the Olympiad number i should be prepared by pi people for ti days, the preparation for the Olympiad should be a continuous period of time and end exactly one day before the Olympiad. On the day of the Olympiad the juries who have prepared it, already do not work on it.For example, if the Olympiad is held on December 9th and the preparation takes 7 people and 6 days, all seven members of the jury will work on the problems of the Olympiad from December, 3rd to December, 8th (the jury members won't be working on the problems of this Olympiad on December 9th, that is, some of them can start preparing problems for some other Olympiad). And if the Olympiad is held on November 3rd and requires 5 days of training, the members of the jury will work from October 29th to November 2nd.In order not to overload the jury the following rule was introduced: one member of the jury can not work on the same day on the tasks for different Olympiads. Write a program that determines what the minimum number of people must be part of the jury so that all Olympiads could be prepared in time.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"529"This Christmas Santa gave Masha a magic picture and a pencil. The picture consists of n points connected by m segments (they might cross in any way, that doesn't matter). No two segments connect the same pair of points, and no segment connects the point to itself. Masha wants to color some segments in order paint a hedgehog. In Mashas mind every hedgehog consists of a tail and some spines. She wants to paint the tail that satisfies the following conditions:   Only segments already presented on the picture can be painted;  The tail should be continuous, i.e. consists of some sequence of points, such that every two neighbouring points are connected by a colored segment;  The numbers of points from the beginning of the tail to the end should strictly increase. Masha defines the length of the tail as the number of points in it. Also, she wants to paint some spines. To do so, Masha will paint all the segments, such that one of their ends is the endpoint of the tail. Masha defines the beauty of a hedgehog as the length of the tail multiplied by the number of spines. Masha wants to color the most beautiful hedgehog. Help her calculate what result she may hope to get.Note that according to Masha's definition of a hedgehog, one segment may simultaneously serve as a spine and a part of the tail (she is a little girl after all). Take a look at the picture for further clarifications.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"530"On a circle lie $$$2n$$$ distinct points, with the following property: however you choose $$$3$$$ chords that connect $$$3$$$ disjoint pairs of points, no point strictly inside the circle belongs to all $$$3$$$ chords. The points are numbered $$$1, \, 2, \, \dots, \, 2n$$$ in clockwise order.Initially, $$$k$$$ chords connect $$$k$$$ pairs of points, in such a way that all the $$$2k$$$ endpoints of these chords are distinct.You want to draw $$$n - k$$$ additional chords that connect the remaining $$$2(n - k)$$$ points (each point must be an endpoint of exactly one chord).In the end, let $$$x$$$ be the total number of intersections among all $$$n$$$ chords. Compute the maximum value that $$$x$$$ can attain if you choose the $$$n - k$$$ chords optimally.Note that the exact position of the $$$2n$$$ points is not relevant, as long as the property stated in the first paragraph holds.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"531"Given an array $$$a$$$ of positive integers with length $$$n$$$, determine if there exist three distinct indices $$$i$$$, $$$j$$$, $$$k$$$ such that $$$a_i + a_j + a_k$$$ ends in the digit $$$3$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"532"Arkady bought an air ticket from a city A to a city C. Unfortunately, there are no direct flights, but there are a lot of flights from A to a city B, and from B to C.There are $$$n$$$ flights from A to B, they depart at time moments $$$a_1$$$, $$$a_2$$$, $$$a_3$$$, ..., $$$a_n$$$ and arrive at B $$$t_a$$$ moments later.There are $$$m$$$ flights from B to C, they depart at time moments $$$b_1$$$, $$$b_2$$$, $$$b_3$$$, ..., $$$b_m$$$ and arrive at C $$$t_b$$$ moments later.The connection time is negligible, so one can use the $$$i$$$-th flight from A to B and the $$$j$$$-th flight from B to C if and only if $$$b_j \ge a_i + t_a$$$.You can cancel at most $$$k$$$ flights. If you cancel a flight, Arkady can not use it.Arkady wants to be in C as early as possible, while you want him to be in C as late as possible. Find the earliest time Arkady can arrive at C, if you optimally cancel $$$k$$$ flights. If you can cancel $$$k$$$ or less flights in such a way that it is not possible to reach C at all, print $$$-1$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"533"You are given an array $$$a$$$ of length $$$n$$$ and array $$$b$$$ of length $$$m$$$ both consisting of only integers $$$0$$$ and $$$1$$$. Consider a matrix $$$c$$$ of size $$$n \times m$$$ formed by following rule: $$$c_{i, j} = a_i \cdot b_j$$$ (i.e. $$$a_i$$$ multiplied by $$$b_j$$$). It's easy to see that $$$c$$$ consists of only zeroes and ones too.How many subrectangles of size (area) $$$k$$$ consisting only of ones are there in $$$c$$$?A subrectangle is an intersection of a consecutive (subsequent) segment of rows and a consecutive (subsequent) segment of columns. I.e. consider four integers $$$x_1, x_2, y_1, y_2$$$ ($$$1 \le x_1 \le x_2 \le n$$$, $$$1 \le y_1 \le y_2 \le m$$$) a subrectangle $$$c[x_1 \dots x_2][y_1 \dots y_2]$$$ is an intersection of the rows $$$x_1, x_1+1, x_1+2, \dots, x_2$$$ and the columns $$$y_1, y_1+1, y_1+2, \dots, y_2$$$.The size (area) of a subrectangle is the total number of cells in it.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"534"This is the hard version of the problem. The only difference between the two versions is the constraint on $$$n$$$. You can make hacks only if all versions of the problem are solved.A forest is an undirected graph without cycles (not necessarily connected).Mocha and Diana are friends in Zhijiang, both of them have a forest with nodes numbered from $$$1$$$ to $$$n$$$, and they would like to add edges to their forests such that:   After adding edges, both of their graphs are still forests.  They add the same edges. That is, if an edge $$$(u, v)$$$ is added to Mocha's forest, then an edge $$$(u, v)$$$ is added to Diana's forest, and vice versa. Mocha and Diana want to know the maximum number of edges they can add, and which edges to add.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"535"This is an interactive problem.Omkar has just come across a duck! The duck is walking on a grid with $$$n$$$ rows and $$$n$$$ columns ($$$2 \leq n \leq 25$$$) so that the grid contains a total of $$$n^2$$$ cells. Let's denote by $$$(x, y)$$$ the cell in the $$$x$$$-th row from the top and the $$$y$$$-th column from the left. Right now, the duck is at the cell $$$(1, 1)$$$ (the cell in the top left corner) and would like to reach the cell $$$(n, n)$$$ (the cell in the bottom right corner) by moving either down $$$1$$$ cell or to the right $$$1$$$ cell each second.Since Omkar thinks ducks are fun, he wants to play a game with you based on the movement of the duck. First, for each cell $$$(x, y)$$$ in the grid, you will tell Omkar a nonnegative integer $$$a_{x,y}$$$ not exceeding $$$10^{16}$$$, and Omkar will then put $$$a_{x,y}$$$ uninteresting problems in the cell $$$(x, y)$$$. After that, the duck will start their journey from $$$(1, 1)$$$ to $$$(n, n)$$$. For each cell $$$(x, y)$$$ that the duck crosses during their journey (including the cells $$$(1, 1)$$$ and $$$(n, n)$$$), the duck will eat the $$$a_{x,y}$$$ uninteresting problems in that cell. Once the duck has completed their journey, Omkar will measure their mass to determine the total number $$$k$$$ of uninteresting problems that the duck ate on their journey, and then tell you $$$k$$$.Your challenge, given $$$k$$$, is to exactly reproduce the duck's path, i. e. to tell Omkar precisely which cells the duck crossed on their journey. To be sure of your mastery of this game, Omkar will have the duck complete $$$q$$$ different journeys ($$$1 \leq q \leq 10^3$$$). Note that all journeys are independent: at the beginning of each journey, the cell $$$(x, y)$$$ will still contain $$$a_{x,y}$$$ uninteresting tasks.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"536"Petya and Vasya are competing with each other in a new interesting game as they always do.At the beginning of the game Petya has to come up with an array of $$$N$$$ positive integers. Sum of all elements in his array should be equal to $$$S$$$. Then Petya has to select an integer $$$K$$$ such that $$$0 \leq K \leq S$$$.In order to win, Vasya has to find a non-empty subarray in Petya's array such that the sum of all selected elements equals to either $$$K$$$ or $$$S - K$$$. Otherwise Vasya loses.You are given integers $$$N$$$ and $$$S$$$. You should determine if Petya can win, considering Vasya plays optimally. If Petya can win, help him to do that.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"537"The only difference between easy and hard versions is the length of the string. You can hack this problem if you solve it. But you can hack the previous problem only if you solve both problems.Kirk has a binary string $$$s$$$ (a string which consists of zeroes and ones) of length $$$n$$$ and he is asking you to find a binary string $$$t$$$ of the same length which satisfies the following conditions: For any $$$l$$$ and $$$r$$$ ($$$1 \leq l \leq r \leq n$$$) the length of the longest non-decreasing subsequence of the substring $$$s_{l}s_{l+1} \ldots s_{r}$$$ is equal to the length of the longest non-decreasing subsequence of the substring $$$t_{l}t_{l+1} \ldots t_{r}$$$; The number of zeroes in $$$t$$$ is the maximum possible.A non-decreasing subsequence of a string $$$p$$$ is a sequence of indices $$$i_1, i_2, \ldots, i_k$$$ such that $$$i_1 < i_2 < \ldots < i_k$$$ and $$$p_{i_1} \leq p_{i_2} \leq \ldots \leq p_{i_k}$$$. The length of the subsequence is $$$k$$$.If there are multiple substrings which satisfy the conditions, output any.","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"538"As we know, DZY loves playing games. One day DZY decided to play with a n × m matrix. To be more precise, he decided to modify the matrix with exactly k operations.Each modification is one of the following:  Pick some row of the matrix and decrease each element of the row by p. This operation brings to DZY the value of pleasure equal to the sum of elements of the row before the decreasing.  Pick some column of the matrix and decrease each element of the column by p. This operation brings to DZY the value of pleasure equal to the sum of elements of the column before the decreasing. DZY wants to know: what is the largest total value of pleasure he could get after performing exactly k modifications? Please, help him to calculate this value.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"539"Given $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$. You can perform the following operation on them:  select any element $$$a_i$$$ ($$$1 \le i \le n$$$) and divide it by $$$2$$$ (round down). In other words, you can replace any selected element $$$a_i$$$ with the value $$$\left \lfloor \frac{a_i}{2}\right\rfloor$$$ (where $$$\left \lfloor x \right\rfloor$$$ is – round down the real number $$$x$$$). Output the minimum number of operations that must be done for a sequence of integers to become strictly increasing (that is, for the condition $$$a_1 \lt a_2 \lt \dots \lt a_n$$$ to be satisfied). Or determine that it is impossible to obtain such a sequence. Note that elements cannot be swapped. The only possible operation is described above.For example, let $$$n = 3$$$ and a sequence of numbers $$$[3, 6, 5]$$$ be given. Then it is enough to perform two operations on it:   Write the number $$$\left \lfloor \frac{6}{2}\right\rfloor = 3$$$ instead of the number $$$a_2=6$$$ and get the sequence $$$[3, 3, 5]$$$;  Then replace $$$a_1=3$$$ with $$$\left \lfloor \frac{3}{2}\right\rfloor = 1$$$ and get the sequence $$$[1, 3, 5]$$$. The resulting sequence is strictly increasing because $$$1 \lt 3 \lt 5$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"540"There are $$$n$$$ students standing in a circle in some order. The index of the $$$i$$$-th student is $$$p_i$$$. It is guaranteed that all indices of students are distinct integers from $$$1$$$ to $$$n$$$ (i. e. they form a permutation).Students want to start a round dance. A clockwise round dance can be started if the student $$$2$$$ comes right after the student $$$1$$$ in clockwise order (there are no students between them), the student $$$3$$$ comes right after the student $$$2$$$ in clockwise order, and so on, and the student $$$n$$$ comes right after the student $$$n - 1$$$ in clockwise order. A counterclockwise round dance is almost the same thing — the only difference is that the student $$$i$$$ should be right after the student $$$i - 1$$$ in counterclockwise order (this condition should be met for every $$$i$$$ from $$$2$$$ to $$$n$$$). For example, if the indices of students listed in clockwise order are $$$[2, 3, 4, 5, 1]$$$, then they can start a clockwise round dance. If the students have indices $$$[3, 2, 1, 4]$$$ in clockwise order, then they can start a counterclockwise round dance.Your task is to determine whether it is possible to start a round dance. Note that the students cannot change their positions before starting the dance; they cannot swap or leave the circle, and no other student can enter the circle. You have to answer $$$q$$$ independent queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"541"A festival will be held in a town's main street. There are n sections in the main street. The sections are numbered 1 through n from left to right. The distance between each adjacent sections is 1.In the festival m fireworks will be launched. The i-th (1 ≤ i ≤ m) launching is on time ti at section ai. If you are at section x (1 ≤ x ≤ n) at the time of i-th launching, you'll gain happiness value bi - |ai - x| (note that the happiness value might be a negative value).You can move up to d length units in a unit time interval, but it's prohibited to go out of the main street. Also you can be in an arbitrary section at initial time moment (time equals to 1), and want to maximize the sum of happiness that can be gained from watching fireworks. Find the maximum total happiness.Note that two or more fireworks can be launched at the same time.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"542"You are given $$$n$$$ segments on the coordinate axis. The $$$i$$$-th segment is $$$[l_i, r_i]$$$. Let's denote the set of all integer points belonging to the $$$i$$$-th segment as $$$S_i$$$.Let $$$A \cup B$$$ be the union of two sets $$$A$$$ and $$$B$$$, $$$A \cap B$$$ be the intersection of two sets $$$A$$$ and $$$B$$$, and $$$A \oplus B$$$ be the symmetric difference of $$$A$$$ and $$$B$$$ (a set which contains all elements of $$$A$$$ and all elements of $$$B$$$, except for the ones that belong to both sets).Let $$$[\mathbin{op}_1, \mathbin{op}_2, \dots, \mathbin{op}_{n-1}]$$$ be an array where each element is either $$$\cup$$$, $$$\oplus$$$, or $$$\cap$$$. Over all $$$3^{n-1}$$$ ways to choose this array, calculate the sum of the following values:$$$$$$|(((S_1\ \mathbin{op}_1\ S_2)\ \mathbin{op}_2\ S_3)\ \mathbin{op}_3\ S_4)\ \dots\ \mathbin{op}_{n-1}\ S_n|$$$$$$In this expression, $$$|S|$$$ denotes the size of the set $$$S$$$.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"543"In order to celebrate Twice's 5th anniversary, Tzuyu and Sana decided to play a game.Tzuyu gave Sana two integers $$$a$$$ and $$$b$$$ and a really important quest.In order to complete the quest, Sana has to output the smallest possible value of ($$$a \oplus x$$$) + ($$$b \oplus x$$$) for any given $$$x$$$, where $$$\oplus$$$ denotes the bitwise XOR operation. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"544"During a break in the buffet of the scientific lyceum of the Kingdom of Kremland, there was formed a queue of $$$n$$$ high school students numbered from $$$1$$$ to $$$n$$$. Initially, each student $$$i$$$ is on position $$$i$$$. Each student $$$i$$$ is characterized by two numbers — $$$a_i$$$ and $$$b_i$$$. Dissatisfaction of the person $$$i$$$ equals the product of $$$a_i$$$ by the number of people standing to the left of his position, add the product $$$b_i$$$ by the number of people standing to the right of his position. Formally, the dissatisfaction of the student $$$i$$$, which is on the position $$$j$$$, equals $$$a_i \cdot (j-1) + b_i \cdot (n-j)$$$.The director entrusted Stas with the task: rearrange the people in the queue so that minimize the total dissatisfaction.Although Stas is able to solve such problems, this was not given to him. He turned for help to you.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"545"Recall that MEX of an array is a minimum non-negative integer that does not belong to the array. Examples:  for the array $$$[0, 0, 1, 0, 2]$$$ MEX equals to $$$3$$$ because numbers $$$0, 1$$$ and $$$2$$$ are presented in the array and $$$3$$$ is the minimum non-negative integer not presented in the array;  for the array $$$[1, 2, 3, 4]$$$ MEX equals to $$$0$$$ because $$$0$$$ is the minimum non-negative integer not presented in the array;  for the array $$$[0, 1, 4, 3]$$$ MEX equals to $$$2$$$ because $$$2$$$ is the minimum non-negative integer not presented in the array. You are given an empty array $$$a=[]$$$ (in other words, a zero-length array). You are also given a positive integer $$$x$$$.You are also given $$$q$$$ queries. The $$$j$$$-th query consists of one integer $$$y_j$$$ and means that you have to append one element $$$y_j$$$ to the array. The array length increases by $$$1$$$ after a query.In one move, you can choose any index $$$i$$$ and set $$$a_i := a_i + x$$$ or $$$a_i := a_i - x$$$ (i.e. increase or decrease any element of the array by $$$x$$$). The only restriction is that $$$a_i$$$ cannot become negative. Since initially the array is empty, you can perform moves only after the first query.You have to maximize the MEX (minimum excluded) of the array if you can perform any number of such operations (you can even perform the operation multiple times with one element).You have to find the answer after each of $$$q$$$ queries (i.e. the $$$j$$$-th answer corresponds to the array of length $$$j$$$).Operations are discarded before each query. I.e. the array $$$a$$$ after the $$$j$$$-th query equals to $$$[y_1, y_2, \dots, y_j]$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"546"There are n piles of pebbles on the table, the i-th pile contains ai pebbles. Your task is to paint each pebble using one of the k given colors so that for each color c and any two piles i and j the difference between the number of pebbles of color c in pile i and number of pebbles of color c in pile j is at most one.In other words, let's say that bi, c is the number of pebbles of color c in the i-th pile. Then for any 1 ≤ c ≤ k, 1 ≤ i, j ≤ n the following condition must be satisfied |bi, c - bj, c| ≤ 1. It isn't necessary to use all k colors: if color c hasn't been used in pile i, then bi, c is considered to be zero.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"547"Some large corporation where Polycarpus works has its own short message service center (SMSC). The center's task is to send all sorts of crucial information. Polycarpus decided to check the efficiency of the SMSC. For that, he asked to give him the statistics of the performance of the SMSC for some period of time. In the end, Polycarpus got a list of n tasks that went to the SMSC of the corporation. Each task was described by the time it was received by the SMSC and the number of text messages to send. More formally, the i-th task was described by two integers ti and ci — the receiving time (the second) and the number of the text messages, correspondingly.Polycarpus knows that the SMSC cannot send more than one text message per second. The SMSC uses a queue to organize its work. Consider a time moment x, the SMSC work at that moment as follows:  If at the time moment x the queue is not empty, then SMSC sends one message from the queue (SMSC gets the message from the head of the queue). Otherwise it doesn't send messages at the time moment x.  If at the time moment x SMSC receives a task, then it adds to the queue all the messages from this task (SMSC adds messages to the tail of the queue). Note, that the messages from the task cannot be send at time moment x. That's because the decision about sending message or not is made at point 1 before adding these messages to the queue. Given the information about all n tasks, Polycarpus wants to count two values: the time when the last text message was sent and the maximum size of the queue at some time. Help him count these two characteristics he needs to evaluate the efficiency of the SMSC.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"548Alice and Bob received $$$n$$$ candies from their parents. Each candy weighs either 1 gram or 2 grams. Now they want to divide all candies among themselves fairly so that the total weight of Alice's candies is equal to the total weight of Bob's candies.Check if they can do that.Note that candies are not allowed to be cut in half.,['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"549A tree is a graph with n vertices and exactly n - 1 edges; this graph should meet the following condition: there exists exactly one shortest (by number of edges) path between any pair of its vertices.A subtree of a tree T is a tree with both vertices and edges as subsets of vertices and edges of T.You're given a tree with n vertices. Consider its vertices numbered with integers from 1 to n. Additionally an integer is written on every vertex of this tree. Initially the integer written on the i-th vertex is equal to vi. In one move you can apply the following operation:  Select the subtree of the given tree that includes the vertex with number 1.  Increase (or decrease) by one all the integers which are written on the vertices of that subtree. Calculate the minimum number of moves that is required to make all the integers written on the vertices of the given tree equal to zero.,['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"550"There are $$$n$$$ block towers in a row, where tower $$$i$$$ has a height of $$$a_i$$$. You're part of a building crew, and you want to make the buildings look as nice as possible. In a single day, you can perform the following operation:  Choose two indices $$$i$$$ and $$$j$$$ ($$$1 \leq i, j \leq n$$$; $$$i \neq j$$$), and move a block from tower $$$i$$$ to tower $$$j$$$. This essentially decreases $$$a_i$$$ by $$$1$$$ and increases $$$a_j$$$ by $$$1$$$. You think the ugliness of the buildings is the height difference between the tallest and shortest buildings. Formally, the ugliness is defined as $$$\max(a)-\min(a)$$$. What's the minimum possible ugliness you can achieve, after any number of days?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"551"The Little Elephant loves Ukraine very much. Most of all he loves town Rozdol (ukr. ""Rozdil"").However, Rozdil is dangerous to settle, so the Little Elephant wants to go to some other town. The Little Elephant doesn't like to spend much time on travelling, so for his journey he will choose a town that needs minimum time to travel to. If there are multiple such cities, then the Little Elephant won't go anywhere.For each town except for Rozdil you know the time needed to travel to this town. Find the town the Little Elephant will go to or print ""Still Rozdil"", if he stays in Rozdil.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"552"Все готовятся к VK Fest 2021! Для того, чтобы зрителям была лучше видна главная сцена, планируется построить амфитеатр. В этой задаче мы будем рассматривать его сбоку — схематично он будет иметь форму лестницы из $$$n$$$ одинаковых квадратов. Лестница — это одна или более башен квадратов, выстроенных в ряд, где высоты башен невозрастают слева направо.На следующем рисунке можно видеть три разные фигуры из $$$12$$$ квадратов. Первые две фигуры — лестницы, а третья — нет.  Из эстетических соображений было решено, что амфитеатр должен быть симметричным. Формально, амфитеатр называется симметричным, если при отражении его схемы относительно прямой $$$x = y$$$ получается тот же самый рисунок (где ось $$$x$$$ направлена слева направо, а ось $$$y$$$ — снизу вверх). Например, первая лестница на рисунке выше — симметричная, а вторая — нет.  Кроме того, амфитеатр должен быть максимально компактным — а именно, сторона минимального квадрата, внутрь которого можно его поместить, должна быть как можно меньше.По заданному числу $$$n$$$ нарисуйте схему амфитеатра из ровно $$$n$$$ квадратов, удовлетворяющую всем условиям.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"553"A pair of positive integers $$$(a,b)$$$ is called special if $$$\lfloor \frac{a}{b} \rfloor = a \bmod b$$$. Here, $$$\lfloor \frac{a}{b} \rfloor$$$ is the result of the integer division between $$$a$$$ and $$$b$$$, while $$$a \bmod b$$$ is its remainder.You are given two integers $$$x$$$ and $$$y$$$. Find the number of special pairs $$$(a,b)$$$ such that $$$1\leq a \leq x$$$ and $$$1 \leq b \leq y$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"554"You are given two lists of segments $$$[al_1, ar_1], [al_2, ar_2], \dots, [al_n, ar_n]$$$ and $$$[bl_1, br_1], [bl_2, br_2], \dots, [bl_n, br_n]$$$.Initially, all segments $$$[al_i, ar_i]$$$ are equal to $$$[l_1, r_1]$$$ and all segments $$$[bl_i, br_i]$$$ are equal to $$$[l_2, r_2]$$$.In one step, you can choose one segment (either from the first or from the second list) and extend it by $$$1$$$. In other words, suppose you've chosen segment $$$[x, y]$$$ then you can transform it either into $$$[x - 1, y]$$$ or into $$$[x, y + 1]$$$.Let's define a total intersection $$$I$$$ as the sum of lengths of intersections of the corresponding pairs of segments, i.e. $$$\sum\limits_{i=1}^{n}{\text{intersection_length}([al_i, ar_i], [bl_i, br_i])}$$$. Empty intersection has length $$$0$$$ and length of a segment $$$[x, y]$$$ is equal to $$$y - x$$$.What is the minimum number of steps you need to make $$$I$$$ greater or equal to $$$k$$$?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"555"There are $$$n$$$ traps numbered from $$$1$$$ to $$$n$$$. You will go through them one by one in order. The $$$i$$$-th trap deals $$$a_i$$$ base damage to you.Instead of going through a trap, you can jump it over. You can jump over no more than $$$k$$$ traps. If you jump over a trap, it does not deal any damage to you. But there is an additional rule: if you jump over a trap, all next traps damages increase by $$$1$$$ (this is a bonus damage).Note that if you jump over a trap, you don't get any damage (neither base damage nor bonus damage). Also, the bonus damage stacks so, for example, if you go through a trap $$$i$$$ with base damage $$$a_i$$$, and you have already jumped over $$$3$$$ traps, you get $$$(a_i + 3)$$$ damage.You have to find the minimal damage that it is possible to get if you are allowed to jump over no more than $$$k$$$ traps.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"556"Julia is conducting an experiment in her lab. She placed several luminescent bacterial colonies in a horizontal testtube. Different types of bacteria can be distinguished by the color of light they emit. Julia marks types of bacteria with small Latin letters ""a"", ..., ""z"".The testtube is divided into n consecutive regions. Each region is occupied by a single colony of a certain bacteria type at any given moment. Hence, the population of the testtube at any moment can be described by a string of n Latin characters.Sometimes a colony can decide to conquer another colony in one of the adjacent regions. When that happens, the attacked colony is immediately eliminated and replaced by a colony of the same type as the attacking colony, while the attacking colony keeps its type. Note that a colony can only attack its neighbours within the boundaries of the testtube. At any moment, at most one attack can take place.For example, consider a testtube with population ""babb"". There are six options for an attack that may happen next: the first colony attacks the second colony (1 → 2), the resulting population is ""bbbb""; 2 → 1, the result is ""aabb""; 2 → 3, the result is ""baab""; 3 → 2, the result is ""bbbb"" (note that the result is the same as the first option); 3 → 4 or 4 → 3, the population does not change.The pattern of attacks is rather unpredictable. Julia is now wondering how many different configurations of bacteria in the testtube she can obtain after a sequence of attacks takes place (it is possible that no attacks will happen at all). Since this number can be large, find it modulo 109 + 7.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"557"There are $$$n$$$ TV shows you want to watch. Suppose the whole time is split into equal parts called ""minutes"". The $$$i$$$-th of the shows is going from $$$l_i$$$-th to $$$r_i$$$-th minute, both ends inclusive.You need a TV to watch a TV show and you can't watch two TV shows which air at the same time on the same TV, so it is possible you will need multiple TVs in some minutes. For example, if segments $$$[l_i, r_i]$$$ and $$$[l_j, r_j]$$$ intersect, then shows $$$i$$$ and $$$j$$$ can't be watched simultaneously on one TV.Once you start watching a show on some TV it is not possible to ""move"" it to another TV (since it would be too distracting), or to watch another show on the same TV until this show ends.There is a TV Rental shop near you. It rents a TV for $$$x$$$ rupees, and charges $$$y$$$ ($$$y < x$$$) rupees for every extra minute you keep the TV. So in order to rent a TV for minutes $$$[a; b]$$$ you will need to pay $$$x + y \cdot (b - a)$$$. You can assume, that taking and returning of the TV doesn't take any time and doesn't distract from watching other TV shows. Find the minimum possible cost to view all shows. Since this value could be too large, print it modulo $$$10^9 + 7$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"558"NN is an experienced internet user and that means he spends a lot of time on the social media. Once he found the following image on the Net, which asked him to compare the sizes of inner circles:  It turned out that the circles are equal. NN was very surprised by this fact, so he decided to create a similar picture himself.He managed to calculate the number of outer circles $$$n$$$ and the radius of the inner circle $$$r$$$. NN thinks that, using this information, you can exactly determine the radius of the outer circles $$$R$$$ so that the inner circle touches all of the outer ones externally and each pair of neighboring outer circles also touches each other. While NN tried very hard to guess the required radius, he didn't manage to do that. Help NN find the required radius for building the required picture.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"559"Heidi found out that the Daleks have created a network of bidirectional Time Corridors connecting different destinations (at different times!). She suspects that they are planning another invasion on the entire Space and Time. In order to counter the invasion, she plans to deploy a trap in the Time Vortex, along a carefully chosen Time Corridor. She knows that tinkering with the Time Vortex is dangerous, so she consulted the Doctor on how to proceed. She has learned the following:  Different Time Corridors require different amounts of energy to keep stable.  Daleks are unlikely to use all corridors in their invasion. They will pick a set of Corridors that requires the smallest total energy to maintain, yet still makes (time) travel possible between any two destinations (for those in the know: they will use a minimum spanning tree).  Setting the trap may modify the energy required to keep the Corridor stable. Heidi decided to carry out a field test and deploy one trap, placing it along the first Corridor. But she needs to know whether the Daleks are going to use this corridor after the deployment of the trap. She gives you a map of Time Corridors (an undirected graph) with energy requirements for each Corridor.For a Corridor $$$c$$$, $$$E_{max}(c)$$$ is the largest $$$e \le 10^9$$$ such that if we changed the required amount of energy of $$$c$$$ to $$$e$$$, then the Daleks may still be using $$$c$$$ in their invasion (that is, it belongs to some minimum spanning tree). Your task is to calculate $$$E_{max}(c_1)$$$ for the Corridor $$$c_1$$$ that Heidi plans to arm with a trap, which is the first edge in the graph.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"560"Little Vlad is fond of popular computer game Bota-2. Recently, the developers announced the new add-on named Bota-3. Of course, Vlad immediately bought only to find out his computer is too old for the new game and needs to be updated.There are n video cards in the shop, the power of the i-th video card is equal to integer value ai. As Vlad wants to be sure the new game will work he wants to buy not one, but several video cards and unite their powers using the cutting-edge technology. To use this technology one of the cards is chosen as the leading one and other video cards are attached to it as secondary. For this new technology to work it's required that the power of each of the secondary video cards is divisible by the power of the leading video card. In order to achieve that the power of any secondary video card can be reduced to any integer value less or equal than the current power. However, the power of the leading video card should remain unchanged, i.e. it can't be reduced.Vlad has an infinite amount of money so he can buy any set of video cards. Help him determine which video cards he should buy such that after picking the leading video card and may be reducing some powers of others to make them work together he will get the maximum total value of video power.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"561"Businessman Divan loves chocolate! Today he came to a store to buy some chocolate. Like all businessmen, Divan knows the value of money, so he will not buy too expensive chocolate. At the same time, too cheap chocolate tastes bad, so he will not buy it as well.The store he came to has $$$n$$$ different chocolate bars, and the price of the $$$i$$$-th chocolate bar is $$$a_i$$$ dollars. Divan considers a chocolate bar too expensive if it costs strictly more than $$$r$$$ dollars. Similarly, he considers a bar of chocolate to be too cheap if it costs strictly less than $$$l$$$ dollars. Divan will not buy too cheap or too expensive bars.Divan is not going to spend all his money on chocolate bars, so he will spend at most $$$k$$$ dollars on chocolates.Please determine the maximum number of chocolate bars Divan can buy.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"562"Vlad, like everyone else, loves to sleep very much.Every day Vlad has to do $$$n$$$ things, each at a certain time. For each of these things, he has an alarm clock set, the $$$i$$$-th of them is triggered on $$$h_i$$$ hours $$$m_i$$$ minutes every day ($$$0 \le h_i < 24, 0 \le m_i < 60$$$). Vlad uses the $$$24$$$-hour time format, so after $$$h=12, m=59$$$ comes $$$h=13, m=0$$$ and after $$$h=23, m=59$$$ comes $$$h=0, m=0$$$.This time Vlad went to bed at $$$H$$$ hours $$$M$$$ minutes ($$$0 \le H < 24, 0 \le M < 60$$$) and asks you to answer: how much he will be able to sleep until the next alarm clock.If any alarm clock rings at the time when he went to bed, then he will sleep for a period of time of length $$$0$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"563"There are many freight trains departing from Kirnes planet every day. One day on that planet consists of $$$h$$$ hours, and each hour consists of $$$m$$$ minutes, where $$$m$$$ is an even number. Currently, there are $$$n$$$ freight trains, and they depart every day at the same time: $$$i$$$-th train departs at $$$h_i$$$ hours and $$$m_i$$$ minutes.The government decided to add passenger trams as well: they plan to add a regular tram service with half-hour intervals. It means that the first tram of the day must depart at $$$0$$$ hours and $$$t$$$ minutes, where $$$0 \le t < {m \over 2}$$$, the second tram departs $$$m \over 2$$$ minutes after the first one and so on. This schedule allows exactly two passenger trams per hour, which is a great improvement.To allow passengers to board the tram safely, the tram must arrive $$$k$$$ minutes before. During the time when passengers are boarding the tram, no freight train can depart from the planet. However, freight trains are allowed to depart at the very moment when the boarding starts, as well as at the moment when the passenger tram departs. Note that, if the first passenger tram departs at $$$0$$$ hours and $$$t$$$ minutes, where $$$t < k$$$, then the freight trains can not depart during the last $$$k - t$$$ minutes of the day.    A schematic picture of the correct way to run passenger trams. Here $$$h=2$$$ (therefore, the number of passenger trams is $$$2h=4$$$), the number of freight trains is $$$n=6$$$. The passenger trams are marked in red (note that the spaces between them are the same). The freight trains are marked in blue. Time segments of length $$$k$$$ before each passenger tram are highlighted in red. Note that there are no freight trains inside these segments. Unfortunately, it might not be possible to satisfy the requirements of the government without canceling some of the freight trains. Please help the government find the optimal value of $$$t$$$ to minimize the number of canceled freight trains in case all passenger trams depart according to schedule.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"564"There is a square of size $$$10^6 \times 10^6$$$ on the coordinate plane with four points $$$(0, 0)$$$, $$$(0, 10^6)$$$, $$$(10^6, 0)$$$, and $$$(10^6, 10^6)$$$ as its vertices.You are going to draw segments on the plane. All segments are either horizontal or vertical and intersect with at least one side of the square.Now you are wondering how many pieces this square divides into after drawing all segments. Write a program calculating the number of pieces of the square.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"565"You have an $$$n \times n$$$ chessboard and $$$k$$$ rooks. Rows of this chessboard are numbered by integers from $$$1$$$ to $$$n$$$ from top to bottom and columns of this chessboard are numbered by integers from $$$1$$$ to $$$n$$$ from left to right. The cell $$$(x, y)$$$ is the cell on the intersection of row $$$x$$$ and collumn $$$y$$$ for $$$1 \leq x \leq n$$$ and $$$1 \leq y \leq n$$$.The arrangement of rooks on this board is called good, if no rook is beaten by another rook.A rook beats all the rooks that shares the same row or collumn with it.The good arrangement of rooks on this board is called not stable, if it is possible to move one rook to the adjacent cell so arrangement becomes not good. Otherwise, the good arrangement is stable. Here, adjacent cells are the cells that share a side.  Such arrangement of $$$3$$$ rooks on the $$$4 \times 4$$$ chessboard is good, but it is not stable: the rook from $$$(1, 1)$$$ can be moved to the adjacent cell $$$(2, 1)$$$ and rooks on cells $$$(2, 1)$$$ and $$$(2, 4)$$$ will beat each other. Please, find any stable arrangement of $$$k$$$ rooks on the $$$n \times n$$$ chessboard or report that there is no such arrangement.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"566"Родители Васи хотят, чтобы он как можно лучше учился. Поэтому если он получает подряд три положительные оценки («четвёрки» или «пятёрки»), они дарят ему подарок. Соответственно, оценки «единица», «двойка» и «тройка» родители Васи считают плохими. Когда Вася получает подряд три хорошие оценки, ему сразу вручают подарок, но для того, чтобы получить ещё один подарок, ему вновь надо получить подряд ещё три хорошие оценки.Например, если Вася получит подряд пять «четвёрок» оценок, а потом «двойку», то ему дадут только один подарок, а вот если бы «четвёрок» было уже шесть, то подарков было бы два. За месяц Вася получил n оценок. Вам предстоит посчитать количество подарков, которые получил Вася. Оценки будут даны именно в том порядке, в котором Вася их получал. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"567"Alice's potion making professor gave the following assignment to his students: brew a potion using $$$n$$$ ingredients, such that the proportion of ingredient $$$i$$$ in the final potion is $$$r_i > 0$$$ (and $$$r_1 + r_2 + \cdots + r_n = 1$$$).He forgot the recipe, and now all he remembers is a set of $$$n-1$$$ facts of the form, ""ingredients $$$i$$$ and $$$j$$$ should have a ratio of $$$x$$$ to $$$y$$$"" (i.e., if $$$a_i$$$ and $$$a_j$$$ are the amounts of ingredient $$$i$$$ and $$$j$$$ in the potion respectively, then it must hold $$$a_i/a_j = x/y$$$), where $$$x$$$ and $$$y$$$ are positive integers. However, it is guaranteed that the set of facts he remembers is sufficient to uniquely determine the original values $$$r_i$$$.He decided that he will allow the students to pass the class as long as they submit a potion which satisfies all of the $$$n-1$$$ requirements (there may be many such satisfactory potions), and contains a positive integer amount of each ingredient.Find the minimum total amount of ingredients needed to make a potion which passes the class. As the result can be very large, you should print the answer modulo $$$998\,244\,353$$$.","['math', 'number theory', 'trees']","[0, 0, 0, 1, 1, 0, 0, 1]"568"Bizon the Champion isn't just attentive, he also is very hardworking.Bizon the Champion decided to paint his old fence his favorite color, orange. The fence is represented as n vertical planks, put in a row. Adjacent planks have no gap between them. The planks are numbered from the left to the right starting from one, the i-th plank has the width of 1 meter and the height of ai meters.Bizon the Champion bought a brush in the shop, the brush's width is 1 meter. He can make vertical and horizontal strokes with the brush. During a stroke the brush's full surface must touch the fence at all the time (see the samples for the better understanding). What minimum number of strokes should Bizon the Champion do to fully paint the fence? Note that you are allowed to paint the same area of the fence multiple times.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"569"Lee was cleaning his house for the party when he found a messy string under the carpets. Now he'd like to make it clean accurately and in a stylish way...The string $$$s$$$ he found is a binary string of length $$$n$$$ (i. e. string consists only of 0-s and 1-s).In one move he can choose two consecutive characters $$$s_i$$$ and $$$s_{i+1}$$$, and if $$$s_i$$$ is 1 and $$$s_{i + 1}$$$ is 0, he can erase exactly one of them (he can choose which one to erase but he can't erase both characters simultaneously). The string shrinks after erasing.Lee can make an arbitrary number of moves (possibly zero) and he'd like to make the string $$$s$$$ as clean as possible. He thinks for two different strings $$$x$$$ and $$$y$$$, the shorter string is cleaner, and if they are the same length, then the lexicographically smaller string is cleaner.Now you should answer $$$t$$$ test cases: for the $$$i$$$-th test case, print the cleanest possible string that Lee can get by doing some number of moves.Small reminder: if we have two strings $$$x$$$ and $$$y$$$ of the same length then $$$x$$$ is lexicographically smaller than $$$y$$$ if there is a position $$$i$$$ such that $$$x_1 = y_1$$$, $$$x_2 = y_2$$$,..., $$$x_{i - 1} = y_{i - 1}$$$ and $$$x_i < y_i$$$.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"570"Kuriyama Mirai has killed many monsters and got many (namely n) stones. She numbers the stones from 1 to n. The cost of the i-th stone is vi. Kuriyama Mirai wants to know something about these stones so she will ask you two kinds of questions:  She will tell you two numbers, l and r (1 ≤ l ≤ r ≤ n), and you should tell her .  Let ui be the cost of the i-th cheapest stone (the cost that will be on the i-th place if we arrange all the stone costs in non-decreasing order). This time she will tell you two numbers, l and r (1 ≤ l ≤ r ≤ n), and you should tell her . For every question you should give the correct answer, or Kuriyama Mirai will say ""fuyukai desu"" and then become unhappy.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"571"Ivan unexpectedly saw a present from one of his previous birthdays. It is array of $$$n$$$ numbers from $$$1$$$ to $$$200$$$. Array is old and some numbers are hard to read. Ivan remembers that for all elements at least one of its neighbours ls not less than it, more formally:$$$a_{1} \le a_{2}$$$,$$$a_{n} \le a_{n-1}$$$ and$$$a_{i} \le max(a_{i-1}, \,\, a_{i+1})$$$ for all $$$i$$$ from $$$2$$$ to $$$n-1$$$.Ivan does not remember the array and asks to find the number of ways to restore it. Restored elements also should be integers from $$$1$$$ to $$$200$$$. Since the number of ways can be big, print it modulo $$$998244353$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"572There are n cities on a two dimensional Cartesian plane. The distance between two cities is equal to the Manhattan distance between them (see the Notes for definition). A Hamiltonian cycle of the cities is defined as a permutation of all n cities. The length of this Hamiltonian cycle is defined as the sum of the distances between adjacent cities in the permutation plus the distance between the first and final city in the permutation. Please compute the longest possible length of a Hamiltonian cycle of the given cities.,['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"573"Having written another programming contest, three Rabbits decided to grab some lunch. The coach gave the team exactly k time units for the lunch break.The Rabbits have a list of n restaurants to lunch in: the i-th restaurant is characterized by two integers fi and ti. Value ti shows the time the Rabbits need to lunch in the i-th restaurant. If time ti exceeds the time k that the coach has given for the lunch break, then the Rabbits' joy from lunching in this restaurant will equal fi - (ti - k). Otherwise, the Rabbits get exactly fi units of joy.Your task is to find the value of the maximum joy the Rabbits can get from the lunch, depending on the restaurant. The Rabbits must choose exactly one restaurant to lunch in. Note that the joy value isn't necessarily a positive value. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"574"You are given an integer $$$n$$$ and a string $$$s$$$ consisting of $$$2^n$$$ lowercase letters of the English alphabet. The characters of the string $$$s$$$ are $$$s_0s_1s_2\cdots s_{2^n-1}$$$.A string $$$t$$$ of length $$$2^n$$$ (whose characters are denoted by $$$t_0t_1t_2\cdots t_{2^n-1}$$$) is a xoration of $$$s$$$ if there exists an integer $$$j$$$ ($$$0\le j \leq 2^n-1$$$) such that, for each $$$0 \leq i \leq 2^n-1$$$, $$$t_i = s_{i \oplus j}$$$ (where $$$\oplus$$$ denotes the operation bitwise XOR).Find the lexicographically minimal xoration of $$$s$$$.A string $$$a$$$ is lexicographically smaller than a string $$$b$$$ if and only if one of the following holds:   $$$a$$$ is a prefix of $$$b$$$, but $$$a \ne b$$$;  in the first position where $$$a$$$ and $$$b$$$ differ, the string $$$a$$$ has a letter that appears earlier in the alphabet than the corresponding letter in $$$b$$$.  ",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"575"This is an easier version of the next problem. The difference is only in constraints.You are given a rectangular $$$n \times m$$$ matrix $$$a$$$. In one move you can choose any column and cyclically shift elements in this column. You can perform this operation as many times as you want (possibly zero). You can perform this operation to a column multiple times.After you are done with cyclical shifts, you compute for every row the maximal value in it. Suppose that for $$$i$$$-th row it is equal $$$r_i$$$. What is the maximal possible value of $$$r_1+r_2+\ldots+r_n$$$?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"576"Polycarp has $$$x$$$ of red and $$$y$$$ of blue candies. Using them, he wants to make gift sets. Each gift set contains either $$$a$$$ red candies and $$$b$$$ blue candies, or $$$a$$$ blue candies and $$$b$$$ red candies. Any candy can belong to at most one gift set.Help Polycarp to find the largest number of gift sets he can create.For example, if $$$x = 10$$$, $$$y = 12$$$, $$$a = 5$$$, and $$$b = 2$$$, then Polycarp can make three gift sets:   In the first set there will be $$$5$$$ red candies and $$$2$$$ blue candies;  In the second set there will be $$$5$$$ blue candies and $$$2$$$ red candies;  In the third set will be $$$5$$$ blue candies and $$$2$$$ red candies. Note that in this example there is one red candy that Polycarp does not use in any gift set.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"577"You a captain of a ship. Initially you are standing in a point $$$(x_1, y_1)$$$ (obviously, all positions in the sea can be described by cartesian plane) and you want to travel to a point $$$(x_2, y_2)$$$. You know the weather forecast — the string $$$s$$$ of length $$$n$$$, consisting only of letters U, D, L and R. The letter corresponds to a direction of wind. Moreover, the forecast is periodic, e.g. the first day wind blows to the side $$$s_1$$$, the second day — $$$s_2$$$, the $$$n$$$-th day — $$$s_n$$$ and $$$(n+1)$$$-th day — $$$s_1$$$ again and so on. Ship coordinates change the following way:  if wind blows the direction U, then the ship moves from $$$(x, y)$$$ to $$$(x, y + 1)$$$;  if wind blows the direction D, then the ship moves from $$$(x, y)$$$ to $$$(x, y - 1)$$$;  if wind blows the direction L, then the ship moves from $$$(x, y)$$$ to $$$(x - 1, y)$$$;  if wind blows the direction R, then the ship moves from $$$(x, y)$$$ to $$$(x + 1, y)$$$. The ship can also either go one of the four directions or stay in place each day. If it goes then it's exactly 1 unit of distance. Transpositions of the ship and the wind add up. If the ship stays in place, then only the direction of wind counts. For example, if wind blows the direction U and the ship moves the direction L, then from point $$$(x, y)$$$ it will move to the point $$$(x - 1, y + 1)$$$, and if it goes the direction U, then it will move to the point $$$(x, y + 2)$$$.You task is to determine the minimal number of days required for the ship to reach the point $$$(x_2, y_2)$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"578"You are given an integer $$$n$$$. You have to apply $$$m$$$ operations to it.In a single operation, you must replace every digit $$$d$$$ of the number with the decimal representation of integer $$$d + 1$$$. For example, $$$1912$$$ becomes $$$21023$$$ after applying the operation once.You have to find the length of $$$n$$$ after applying $$$m$$$ operations. Since the answer can be very large, print it modulo $$$10^9+7$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"579"Vanya has a table consisting of 100 rows, each row contains 100 cells. The rows are numbered by integers from 1 to 100 from bottom to top, the columns are numbered from 1 to 100 from left to right. In this table, Vanya chose n rectangles with sides that go along borders of squares (some rectangles probably occur multiple times). After that for each cell of the table he counted the number of rectangles it belongs to and wrote this number into it. Now he wants to find the sum of values in all cells of the table and as the table is too large, he asks you to help him find the result.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"580"Andryusha goes through a park each day. The squares and paths between them look boring to Andryusha, so he decided to decorate them.The park consists of n squares connected with (n - 1) bidirectional paths in such a way that any square is reachable from any other using these paths. Andryusha decided to hang a colored balloon at each of the squares. The baloons' colors are described by positive integers, starting from 1. In order to make the park varicolored, Andryusha wants to choose the colors in a special way. More precisely, he wants to use such colors that if a, b and c are distinct squares that a and b have a direct path between them, and b and c have a direct path between them, then balloon colors on these three squares are distinct.Andryusha wants to use as little different colors as possible. Help him to choose the colors!","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"581"There is a forest that we model as a plane and live $$$n$$$ rare animals. Animal number $$$i$$$ has its lair in the point $$$(x_{i}, y_{i})$$$. In order to protect them, a decision to build a nature reserve has been made.The reserve must have a form of a circle containing all lairs. There is also a straight river flowing through the forest. All animals drink from this river, therefore it must have at least one common point with the reserve. On the other hand, ships constantly sail along the river, so the reserve must not have more than one common point with the river.For convenience, scientists have made a transformation of coordinates so that the river is defined by $$$y = 0$$$. Check whether it is possible to build a reserve, and if possible, find the minimum possible radius of such a reserve.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"582"Some dwarves that are finishing the StUDY (State University for Dwarven Youngsters) Bachelor courses, have been told ""no genome, no degree"". That means that all dwarves should write a thesis on genome. Dwarven genome is far from simple. It is represented by a string that consists of lowercase Latin letters.Dwarf Misha has already chosen the subject for his thesis: determining by two dwarven genomes, whether they belong to the same race. Two dwarves belong to the same race if we can swap two characters in the first dwarf's genome and get the second dwarf's genome as a result. Help Dwarf Misha and find out whether two gnomes belong to the same race or not.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"583"We get more and more news about DDoS-attacks of popular websites.Arseny is an admin and he thinks that a website is under a DDoS-attack if the total number of requests for a some period of time exceeds $$$100 \cdot t$$$, where $$$t$$$ — the number of seconds in this time segment. Arseny knows statistics on the number of requests per second since the server is booted. He knows the sequence $$$r_1, r_2, \dots, r_n$$$, where $$$r_i$$$ — the number of requests in the $$$i$$$-th second after boot. Determine the length of the longest continuous period of time, which Arseny considers to be a DDoS-attack. A seeking time period should not go beyond the boundaries of the segment $$$[1, n]$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"584"Vladik had started reading a complicated book about algorithms containing n pages. To improve understanding of what is written, his friends advised him to read pages in some order given by permutation P = [p1, p2, ..., pn], where pi denotes the number of page that should be read i-th in turn.Sometimes Vladik’s mom sorted some subsegment of permutation P from position l to position r inclusive, because she loves the order. For every of such sorting Vladik knows number x — what index of page in permutation he should read. He is wondered if the page, which he will read after sorting, has changed. In other words, has px changed? After every sorting Vladik return permutation to initial state, so you can assume that each sorting is independent from each other.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"585"Igor the analyst has adopted n little bunnies. As we all know, bunnies love carrots. Thus, Igor has bought a carrot to be shared between his bunnies. Igor wants to treat all the bunnies equally, and thus he wants to cut the carrot into n pieces of equal area. Formally, the carrot can be viewed as an isosceles triangle with base length equal to 1 and height equal to h. Igor wants to make n - 1 cuts parallel to the base to cut the carrot into n pieces. He wants to make sure that all n pieces have the same area. Can you help Igor determine where to cut the carrot so that each piece have equal area?  Illustration to the first example. ","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"586"Pupils Alice and Ibragim are best friends. It's Ibragim's birthday soon, so Alice decided to gift him a new puzzle. The puzzle can be represented as a matrix with $$$2$$$ rows and $$$n$$$ columns, every element of which is either $$$0$$$ or $$$1$$$. In one move you can swap two values in neighboring cells.More formally, let's number rows $$$1$$$ to $$$2$$$ from top to bottom, and columns $$$1$$$ to $$$n$$$ from left to right. Also, let's denote a cell in row $$$x$$$ and column $$$y$$$ as $$$(x, y)$$$. We consider cells $$$(x_1, y_1)$$$ and $$$(x_2, y_2)$$$ neighboring if $$$|x_1 - x_2| + |y_1 - y_2| = 1$$$.Alice doesn't like the way in which the cells are currently arranged, so she came up with her own arrangement, with which she wants to gift the puzzle to Ibragim. Since you are her smartest friend, she asked you to help her find the minimal possible number of operations in which she can get the desired arrangement. Find this number, or determine that it's not possible to get the new arrangement.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"587"Polycarpus has an array, consisting of n integers a1, a2, ..., an. Polycarpus likes it when numbers in an array match. That's why he wants the array to have as many equal numbers as possible. For that Polycarpus performs the following operation multiple times:  he chooses two elements of the array ai, aj (i ≠ j);  he simultaneously increases number ai by 1 and decreases number aj by 1, that is, executes ai = ai + 1 and aj = aj - 1. The given operation changes exactly two distinct array elements. Polycarpus can apply the described operation an infinite number of times. Now he wants to know what maximum number of equal array elements he can get if he performs an arbitrary number of such operation. Help Polycarpus.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"588Let's call a permutation $$$p$$$ of length $$$n$$$ anti-Fibonacci if the condition $$$p_{i-2} + p_{i-1} \ne p_i$$$ holds for all $$$i$$$ ($$$3 \le i \le n$$$). Recall that the permutation is the array of length $$$n$$$ which contains each integer from $$$1$$$ to $$$n$$$ exactly once.Your task is for a given number $$$n$$$ print $$$n$$$ distinct anti-Fibonacci permutations of length $$$n$$$.,[],"[0, 0, 0, 0, 0, 0, 0, 0]"589"Suppose there is a $$$h \times w$$$ grid consisting of empty or full cells. Let's make some definitions:  $$$r_{i}$$$ is the number of consecutive full cells connected to the left side in the $$$i$$$-th row ($$$1 \le i \le h$$$). In particular, $$$r_i=0$$$ if the leftmost cell of the $$$i$$$-th row is empty.  $$$c_{j}$$$ is the number of consecutive full cells connected to the top end in the $$$j$$$-th column ($$$1 \le j \le w$$$). In particular, $$$c_j=0$$$ if the topmost cell of the $$$j$$$-th column is empty. In other words, the $$$i$$$-th row starts exactly with $$$r_i$$$ full cells. Similarly, the $$$j$$$-th column starts exactly with $$$c_j$$$ full cells.    These are the $$$r$$$ and $$$c$$$ values of some $$$3 \times 4$$$ grid. Black cells are full and white cells are empty. You have values of $$$r$$$ and $$$c$$$. Initially, all cells are empty. Find the number of ways to fill grid cells to satisfy values of $$$r$$$ and $$$c$$$. Since the answer can be very large, find the answer modulo $$$1000000007\,(10^{9} + 7)$$$. In other words, find the remainder after division of the answer by $$$1000000007\,(10^{9} + 7)$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"590"Ivan is fond of genealogy. Currently he is studying a particular genealogical structure, which consists of some people. In this structure every person has either both parents specified, or none. Additionally, each person has exactly one child, except for one special person, who does not have any children. The people in this structure are conveniently numbered from $$$1$$$ to $$$n$$$, and $$$s_i$$$ denotes the child of the person $$$i$$$ (and $$$s_i = 0$$$ for exactly one person who does not have any children).We say that $$$a$$$ is an ancestor of $$$b$$$ if either $$$a = b$$$, or $$$a$$$ has a child, who is an ancestor of $$$b$$$. That is $$$a$$$ is an ancestor for $$$a$$$, $$$s_a$$$, $$$s_{s_a}$$$, etc.We say that person $$$i$$$ is imbalanced in case this person has both parents specified, and the total number of ancestors of one of the parents is at least double the other. Ivan counted the number of imbalanced people in the structure, and got $$$k$$$ people in total. However, he is not sure whether he computed it correctly, and would like to check if there is at least one construction with $$$n$$$ people that have $$$k$$$ imbalanced people in total. Please help him to find one such construction, or determine if it does not exist.","['math', 'trees']","[0, 0, 0, 1, 0, 0, 0, 1]"591"John has just bought a new car and is planning a journey around the country. Country has N cities, some of which are connected by bidirectional roads. There are N - 1 roads and every city is reachable from any other city. Cities are labeled from 1 to N.John first has to select from which city he will start his journey. After that, he spends one day in a city and then travels to a randomly choosen city which is directly connected to his current one and which he has not yet visited. He does this until he can't continue obeying these rules.To select the starting city, he calls his friend Jack for advice. Jack is also starting a big casino business and wants to open casinos in some of the cities (max 1 per city, maybe nowhere). Jack knows John well and he knows that if he visits a city with a casino, he will gamble exactly once before continuing his journey.He also knows that if John enters a casino in a good mood, he will leave it in a bad mood and vice versa. Since he is John's friend, he wants him to be in a good mood at the moment when he finishes his journey. John is in a good mood before starting the journey.In how many ways can Jack select a starting city for John and cities where he will build casinos such that no matter how John travels, he will be in a good mood at the end? Print answer modulo 109 + 7.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"592"It is Professor R's last class of his teaching career. Every time Professor R taught a class, he gave a special problem for the students to solve. You being his favourite student, put your heart into solving it one last time.You are given two polynomials $$$f(x) = a_0 + a_1x + \dots + a_{n-1}x^{n-1}$$$ and $$$g(x) = b_0 + b_1x + \dots + b_{m-1}x^{m-1}$$$, with positive integral coefficients. It is guaranteed that the cumulative GCD of the coefficients is equal to $$$1$$$ for both the given polynomials. In other words, $$$gcd(a_0, a_1, \dots, a_{n-1}) = gcd(b_0, b_1, \dots, b_{m-1}) = 1$$$. Let $$$h(x) = f(x)\cdot g(x)$$$. Suppose that $$$h(x) = c_0 + c_1x + \dots + c_{n+m-2}x^{n+m-2}$$$. You are also given a prime number $$$p$$$. Professor R challenges you to find any $$$t$$$ such that $$$c_t$$$ isn't divisible by $$$p$$$. He guarantees you that under these conditions such $$$t$$$ always exists. If there are several such $$$t$$$, output any of them.As the input is quite large, please use fast input reading methods.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"593"Lenny had an n × m matrix of positive integers. He loved the matrix so much, because each row of the matrix was sorted in non-decreasing order. For the same reason he calls such matrices of integers lovely.One day when Lenny was at school his little brother was playing with Lenny's matrix in his room. He erased some of the entries of the matrix and changed the order of some of its columns. When Lenny got back home he was very upset. Now Lenny wants to recover his matrix.Help him to find an order for the columns of the matrix so that it's possible to fill in the erased entries of the matrix to achieve a lovely matrix again. Note, that you can fill the erased entries of the matrix with any integers.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"594"You are given three positive integers $$$a$$$, $$$b$$$, $$$c$$$ ($$$a < b < c$$$). You have to find three positive integers $$$x$$$, $$$y$$$, $$$z$$$ such that:$$$$$$x \bmod y = a,$$$$$$ $$$$$$y \bmod z = b,$$$$$$ $$$$$$z \bmod x = c.$$$$$$Here $$$p \bmod q$$$ denotes the remainder from dividing $$$p$$$ by $$$q$$$. It is possible to show that for such constraints the answer always exists.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"595"Recently in Divanovo, a huge river locks system was built. There are now $$$n$$$ locks, the $$$i$$$-th of them has the volume of $$$v_i$$$ liters, so that it can contain any amount of water between $$$0$$$ and $$$v_i$$$ liters. Each lock has a pipe attached to it. When the pipe is open, $$$1$$$ liter of water enters the lock every second.The locks system is built in a way to immediately transfer all water exceeding the volume of the lock $$$i$$$ to the lock $$$i + 1$$$. If the lock $$$i + 1$$$ is also full, water will be transferred further. Water exceeding the volume of the last lock pours out to the river.   The picture illustrates $$$5$$$ locks with two open pipes at locks $$$1$$$ and $$$3$$$. Because locks $$$1$$$, $$$3$$$, and $$$4$$$ are already filled, effectively the water goes to locks $$$2$$$ and $$$5$$$. Note that the volume of the $$$i$$$-th lock may be greater than the volume of the $$$i + 1$$$-th lock.To make all locks work, you need to completely fill each one of them. The mayor of Divanovo is interested in $$$q$$$ independent queries. For each query, suppose that initially all locks are empty and all pipes are closed. Then, some pipes are opened simultaneously. For the $$$j$$$-th query the mayor asks you to calculate the minimum number of pipes to open so that all locks are filled no later than after $$$t_j$$$ seconds.Please help the mayor to solve this tricky problem and answer his queries. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"596"You are given $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$ and an integer $$$k$$$. Find the maximum value of $$$i \cdot j - k \cdot (a_i | a_j)$$$ over all pairs $$$(i, j)$$$ of integers with $$$1 \le i < j \le n$$$. Here, $$$|$$$ is the bitwise OR operator.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"597"Professor Vasechkin is studying evolution of worms. Recently he put forward hypotheses that all worms evolve by division. There are n forms of worms. Worms of these forms have lengths a1, a2, ..., an. To prove his theory, professor needs to find 3 different forms that the length of the first form is equal to sum of lengths of the other two forms. Help him to do this.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"598"Another programming contest is over. You got hold of the contest's final results table. The table has the following data. For each team we are shown two numbers: the number of problems and the total penalty time. However, for no team we are shown its final place.You know the rules of comparing the results of two given teams very well. Let's say that team a solved pa problems with total penalty time ta and team b solved pb problems with total penalty time tb. Team a gets a higher place than team b in the end, if it either solved more problems on the contest, or solved the same number of problems but in less total time. In other words, team a gets a higher place than team b in the final results' table if either pa > pb, or pa = pb and ta < tb. It is considered that the teams that solve the same number of problems with the same penalty time share all corresponding places. More formally, let's say there is a group of x teams that solved the same number of problems with the same penalty time. Let's also say that y teams performed better than the teams from this group. In this case all teams from the group share places y + 1, y + 2, ..., y + x. The teams that performed worse than the teams from this group, get their places in the results table starting from the y + x + 1-th place.Your task is to count what number of teams from the given list shared the k-th place. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"599"Imagine that you have a twin brother or sister. Having another person that looks exactly like you seems very unusual. It's hard to say if having something of an alter ego is good or bad. And if you do have a twin, then you very well know what it's like.Now let's imagine a typical morning in your family. You haven't woken up yet, and Mom is already going to work. She has been so hasty that she has nearly forgotten to leave the two of her darling children some money to buy lunches in the school cafeteria. She fished in the purse and found some number of coins, or to be exact, n coins of arbitrary values a1, a2, ..., an. But as Mom was running out of time, she didn't split the coins for you two. So she scribbled a note asking you to split the money equally.As you woke up, you found Mom's coins and read her note. ""But why split the money equally?"" — you thought. After all, your twin is sleeping and he won't know anything. So you decided to act like that: pick for yourself some subset of coins so that the sum of values of your coins is strictly larger than the sum of values of the remaining coins that your twin will have. However, you correctly thought that if you take too many coins, the twin will suspect the deception. So, you've decided to stick to the following strategy to avoid suspicions: you take the minimum number of coins, whose sum of values is strictly more than the sum of values of the remaining coins. On this basis, determine what minimum number of coins you need to take to divide them in the described manner.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"600"A little boy Laurenty has been playing his favourite game Nota for quite a while and is now very hungry. The boy wants to make sausage and cheese sandwiches, but first, he needs to buy a sausage and some cheese.The town where Laurenty lives in is not large. The houses in it are located in two rows, n houses in each row. Laurenty lives in the very last house of the second row. The only shop in town is placed in the first house of the first row.The first and second rows are separated with the main avenue of the city. The adjacent houses of one row are separated by streets.Each crosswalk of a street or an avenue has some traffic lights. In order to cross the street, you need to press a button on the traffic light, wait for a while for the green light and cross the street. Different traffic lights can have different waiting time.The traffic light on the crosswalk from the j-th house of the i-th row to the (j + 1)-th house of the same row has waiting time equal to aij (1 ≤ i ≤ 2, 1 ≤ j ≤ n - 1). For the traffic light on the crossing from the j-th house of one row to the j-th house of another row the waiting time equals bj (1 ≤ j ≤ n). The city doesn't have any other crossings.The boy wants to get to the store, buy the products and go back. The main avenue of the city is wide enough, so the boy wants to cross it exactly once on the way to the store and exactly once on the way back home. The boy would get bored if he had to walk the same way again, so he wants the way home to be different from the way to the store in at least one crossing.    Figure to the first sample. Help Laurenty determine the minimum total time he needs to wait at the crossroads.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"601"Ilya is a very good-natured lion. He likes maths. Of all mathematical objects, his favourite one is matrices. Now he's faced a complicated matrix problem he needs to solve.He's got a square 2n × 2n-sized matrix and 4n integers. You need to arrange all these numbers in the matrix (put each number in a single individual cell) so that the beauty of the resulting matrix with numbers is maximum.The beauty of a 2n × 2n-sized matrix is an integer, obtained by the following algorithm:  Find the maximum element in the matrix. Let's denote it as m.  If n = 0, then the beauty of the matrix equals m. Otherwise, a matrix can be split into 4 non-intersecting 2n - 1 × 2n - 1-sized submatrices, then the beauty of the matrix equals the sum of number m and other four beauties of the described submatrices. As you can see, the algorithm is recursive.Help Ilya, solve the problem and print the resulting maximum beauty of the matrix.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"602"Fishing Prince loves trees, and he especially loves trees with only one centroid. The tree is a connected graph without cycles.A vertex is a centroid of a tree only when you cut this vertex (remove it and remove all edges from this vertex), the size of the largest connected component of the remaining graph is the smallest possible.For example, the centroid of the following tree is $$$2$$$, because when you cut it, the size of the largest connected component of the remaining graph is $$$2$$$ and it can't be smaller.  However, in some trees, there might be more than one centroid, for example:  Both vertex $$$1$$$ and vertex $$$2$$$ are centroids because the size of the largest connected component is $$$3$$$ after cutting each of them.Now Fishing Prince has a tree. He should cut one edge of the tree (it means to remove the edge). After that, he should add one edge. The resulting graph after these two operations should be a tree. He can add the edge that he cut.He wants the centroid of the resulting tree to be unique. Help him and find any possible way to make the operations. It can be proved, that at least one such way always exists.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"603"Someone gave Alyona an array containing n positive integers a1, a2, ..., an. In one operation, Alyona can choose any element of the array and decrease it, i.e. replace with any positive integer that is smaller than the current one. Alyona can repeat this operation as many times as she wants. In particular, she may not apply any operation to the array at all.Formally, after applying some operations Alyona will get an array of n positive integers b1, b2, ..., bn such that 1 ≤ bi ≤ ai for every 1 ≤ i ≤ n. Your task is to determine the maximum possible value of mex of this array.Mex of an array in this problem is the minimum positive integer that doesn't appear in this array. For example, mex of the array containing 1, 3 and 4 is equal to 2, while mex of the array containing 2, 3 and 2 is equal to 1.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"604"The Little Elephant loves to play with color cards.He has n cards, each has exactly two colors (the color of the front side and the color of the back side). Initially, all the cards lay on the table with the front side up. In one move the Little Elephant can turn any card to the other side. The Little Elephant thinks that a set of cards on the table is funny if at least half of the cards have the same color (for each card the color of the upper side is considered).Help the Little Elephant to find the minimum number of moves needed to make the set of n cards funny.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"605"Ashish and Vivek play a game on a matrix consisting of $$$n$$$ rows and $$$m$$$ columns, where they take turns claiming cells. Unclaimed cells are represented by $$$0$$$, while claimed cells are represented by $$$1$$$. The initial state of the matrix is given. There can be some claimed cells in the initial state.In each turn, a player must claim a cell. A cell may be claimed if it is unclaimed and does not share a row or column with any other already claimed cells. When a player is unable to make a move, he loses and the game ends.If Ashish and Vivek take turns to move and Ashish goes first, determine the winner of the game if both of them are playing optimally.Optimal play between two players means that both players choose the best possible strategy to achieve the best possible outcome for themselves.",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"606"Given an array of integer $$$a_1, a_2, \ldots, a_n$$$. In one operation you can make $$$a_i := a_i + 1$$$ if $$$i < n$$$ and $$$a_i \leq a_{i + 1}$$$, or $$$i = n$$$ and $$$a_i \leq a_1$$$.You need to check whether the array $$$a_1, a_2, \ldots, a_n$$$ can become equal to the array $$$b_1, b_2, \ldots, b_n$$$ in some number of operations (possibly, zero). Two arrays $$$a$$$ and $$$b$$$ of length $$$n$$$ are called equal if $$$a_i = b_i$$$ for all integers $$$i$$$ from $$$1$$$ to $$$n$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"607"This is the easy version of the problem. The only difference between the two versions is that the harder version asks additionally for a minimum number of subsegments.Tokitsukaze has a binary string $$$s$$$ of length $$$n$$$, consisting only of zeros and ones, $$$n$$$ is even.Now Tokitsukaze divides $$$s$$$ into the minimum number of contiguous subsegments, and for each subsegment, all bits in each subsegment are the same. After that, $$$s$$$ is considered good if the lengths of all subsegments are even.For example, if $$$s$$$ is ""11001111"", it will be divided into ""11"", ""00"" and ""1111"". Their lengths are $$$2$$$, $$$2$$$, $$$4$$$ respectively, which are all even numbers, so ""11001111"" is good. Another example, if $$$s$$$ is ""1110011000"", it will be divided into ""111"", ""00"", ""11"" and ""000"", and their lengths are $$$3$$$, $$$2$$$, $$$2$$$, $$$3$$$. Obviously, ""1110011000"" is not good.Tokitsukaze wants to make $$$s$$$ good by changing the values of some positions in $$$s$$$. Specifically, she can perform the operation any number of times: change the value of $$$s_i$$$ to '0' or '1'($$$1 \leq i \leq n$$$). Can you tell her the minimum number of operations to make $$$s$$$ good?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"608"Byteland is a beautiful land known because of its beautiful trees.Misha has found a binary tree with $$$n$$$ vertices, numbered from $$$1$$$ to $$$n$$$. A binary tree is an acyclic connected bidirectional graph containing $$$n$$$ vertices and $$$n - 1$$$ edges. Each vertex has a degree at most $$$3$$$, whereas the root is the vertex with the number $$$1$$$ and it has a degree at most $$$2$$$.Unfortunately, the root got infected.The following process happens $$$n$$$ times:  Misha either chooses a non-infected (and not deleted) vertex and deletes it with all edges which have an end in this vertex or just does nothing.  Then, the infection spreads to each vertex that is connected by an edge to an already infected vertex (all already infected vertices remain infected). As Misha does not have much time to think, please tell him what is the maximum number of vertices he can save from the infection (note that deleted vertices are not counted as saved).",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"609"You are given an array $$$a$$$ consisting of $$$n$$$ integers. In one move, you can jump from the position $$$i$$$ to the position $$$i - a_i$$$ (if $$$1 \le i - a_i$$$) or to the position $$$i + a_i$$$ (if $$$i + a_i \le n$$$).For each position $$$i$$$ from $$$1$$$ to $$$n$$$ you want to know the minimum the number of moves required to reach any position $$$j$$$ such that $$$a_j$$$ has the opposite parity from $$$a_i$$$ (i.e. if $$$a_i$$$ is odd then $$$a_j$$$ has to be even and vice versa).",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"610"You are given three strings $$$s$$$, $$$t$$$ and $$$p$$$ consisting of lowercase Latin letters. You may perform any number (possibly, zero) operations on these strings.During each operation you choose any character from $$$p$$$, erase it from $$$p$$$ and insert it into string $$$s$$$ (you may insert this character anywhere you want: in the beginning of $$$s$$$, in the end or between any two consecutive characters). For example, if $$$p$$$ is aba, and $$$s$$$ is de, then the following outcomes are possible (the character we erase from $$$p$$$ and insert into $$$s$$$ is highlighted):  aba $$$\rightarrow$$$ ba, de $$$\rightarrow$$$ ade;  aba $$$\rightarrow$$$ ba, de $$$\rightarrow$$$ dae;  aba $$$\rightarrow$$$ ba, de $$$\rightarrow$$$ dea;  aba $$$\rightarrow$$$ aa, de $$$\rightarrow$$$ bde;  aba $$$\rightarrow$$$ aa, de $$$\rightarrow$$$ dbe;  aba $$$\rightarrow$$$ aa, de $$$\rightarrow$$$ deb;  aba $$$\rightarrow$$$ ab, de $$$\rightarrow$$$ ade;  aba $$$\rightarrow$$$ ab, de $$$\rightarrow$$$ dae;  aba $$$\rightarrow$$$ ab, de $$$\rightarrow$$$ dea; Your goal is to perform several (maybe zero) operations so that $$$s$$$ becomes equal to $$$t$$$. Please determine whether it is possible.Note that you have to answer $$$q$$$ independent queries.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"611"You are given an array $$$a$$$ of $$$n$$$ ($$$n \geq 2$$$) positive integers and an integer $$$p$$$. Consider an undirected weighted graph of $$$n$$$ vertices numbered from $$$1$$$ to $$$n$$$ for which the edges between the vertices $$$i$$$ and $$$j$$$ ($$$i<j$$$) are added in the following manner:  If $$$gcd(a_i, a_{i+1}, a_{i+2}, \dots, a_{j}) = min(a_i, a_{i+1}, a_{i+2}, \dots, a_j)$$$, then there is an edge of weight $$$min(a_i, a_{i+1}, a_{i+2}, \dots, a_j)$$$ between $$$i$$$ and $$$j$$$.  If $$$i+1=j$$$, then there is an edge of weight $$$p$$$ between $$$i$$$ and $$$j$$$. Here $$$gcd(x, y, \ldots)$$$ denotes the greatest common divisor (GCD) of integers $$$x$$$, $$$y$$$, ....Note that there could be multiple edges between $$$i$$$ and $$$j$$$ if both of the above conditions are true, and if both the conditions fail for $$$i$$$ and $$$j$$$, then there is no edge between these vertices.The goal is to find the weight of the minimum spanning tree of this graph.","['graphs', 'number theory']","[0, 0, 1, 0, 1, 0, 0, 0]"612"Jzzhu has picked n apples from his big apple tree. All the apples are numbered from 1 to n. Now he wants to sell them to an apple store. Jzzhu will pack his apples into groups and then sell them. Each group must contain two apples, and the greatest common divisor of numbers of the apples in each group must be greater than 1. Of course, each apple can be part of at most one group.Jzzhu wonders how to get the maximum possible number of groups. Can you help him?",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"613"You are given an array a1, a2, ..., an consisting of n integers, and an integer k. You have to split the array into exactly k non-empty subsegments. You'll then compute the minimum integer on each subsegment, and take the maximum integer over the k obtained minimums. What is the maximum possible integer you can get?Definitions of subsegment and array splitting are given in notes.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"614"Given the string $$$s$$$ of decimal digits (0-9) of length $$$n$$$.A substring is a sequence of consecutive characters of a string. The substring of this string is defined by a pair of indexes — with its left and right ends. So, each pair of indexes ($$$l, r$$$), where $$$1 \le l \le r \le n$$$, corresponds to a substring of the string $$$s$$$. We will define as $$$v(l,r)$$$ the numeric value of the corresponding substring (leading zeros are allowed in it).For example, if $$$n=7$$$, $$$s=$$$""1003004"", then $$$v(1,3)=100$$$, $$$v(2,3)=0$$$ and $$$v(2,7)=3004$$$.You are given $$$n$$$, $$$s$$$ and an integer $$$w$$$ ($$$1 \le w < n$$$).You need to process $$$m$$$ queries, each of which is characterized by $$$3$$$ numbers $$$l_i, r_i, k_i$$$ ($$$1 \le l_i \le r_i \le n; 0 \le k_i \le 8$$$).The answer to the $$$i$$$th query is such a pair of substrings of length $$$w$$$ that if we denote them as $$$(L_1, L_1+w-1)$$$ and $$$(L_2, L_2+w-1)$$$, then:  $$$L_1 \ne L_2$$$, that is, the substrings are different;  the remainder of dividing a number $$$v(L_1, L_1+w-1) \cdot v(l_i, r_i) + v(L_2, L_2 + w - 1)$$$ by $$$9$$$ is equal to $$$k_i$$$. If there are many matching substring pairs, then find a pair where $$$L_1$$$ is as small as possible. If there are many matching pairs in this case, then minimize $$$L_2$$$.Note that the answer may not exist.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"615"This problem is different with hard version only by constraints on total answers lengthIt is an interactive problemVenya joined a tour to the madhouse, in which orderlies play with patients the following game. Orderlies pick a string $$$s$$$ of length $$$n$$$, consisting only of lowercase English letters. The player can ask two types of queries:   ? l r – ask to list all substrings of $$$s[l..r]$$$. Substrings will be returned in random order, and in every substring, all characters will be randomly shuffled.  ! s – guess the string picked by the orderlies. This query can be asked exactly once, after that the game will finish. If the string is guessed correctly, the player wins, otherwise he loses. The player can ask no more than $$$3$$$ queries of the first type.To make it easier for the orderlies, there is an additional limitation: the total number of returned substrings in all queries of the first type must not exceed $$$(n+1)^2$$$.Venya asked you to write a program, which will guess the string by interacting with the orderlies' program and acting by the game's rules.Your program should immediately terminate after guessing the string using a query of the second type. In case your program guessed the string incorrectly, or it violated the game rules, it will receive verdict Wrong answer.Note that in every test case the string is fixed beforehand and will not change during the game, which means that the interactor is not adaptive.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"616"Mike and some bears are playing a game just for fun. Mike is the judge. All bears except Mike are standing in an n × m grid, there's exactly one bear in each cell. We denote the bear standing in column number j of row number i by (i, j). Mike's hands are on his ears (since he's the judge) and each bear standing in the grid has hands either on his mouth or his eyes.  They play for q rounds. In each round, Mike chooses a bear (i, j) and tells him to change his state i. e. if his hands are on his mouth, then he'll put his hands on his eyes or he'll put his hands on his mouth otherwise. After that, Mike wants to know the score of the bears.Score of the bears is the maximum over all rows of number of consecutive bears with hands on their eyes in that row.Since bears are lazy, Mike asked you for help. For each round, tell him the score of these bears after changing the state of a bear selected in that round. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"617"There is a grid with $$$r$$$ rows and $$$c$$$ columns, where the square on the $$$i$$$-th row and $$$j$$$-th column has an integer $$$a_{i, j}$$$ written on it. Initially, all elements are set to $$$0$$$. We are allowed to do the following operation:  Choose indices $$$1 \le i \le r$$$ and $$$1 \le j \le c$$$, then replace all values on the same row or column as $$$(i, j)$$$ with the value xor $$$1$$$. In other words, for all $$$a_{x, y}$$$ where $$$x=i$$$ or $$$y=j$$$ or both, replace $$$a_{x, y}$$$ with $$$a_{x, y}$$$ xor $$$1$$$. You want to form grid $$$b$$$ by doing the above operations a finite number of times. However, some elements of $$$b$$$ are missing and are replaced with '?' instead.Let $$$k$$$ be the number of '?' characters. Among all the $$$2^k$$$ ways of filling up the grid $$$b$$$ by replacing each '?' with '0' or '1', count the number of grids, that can be formed by doing the above operation a finite number of times, starting from the grid filled with $$$0$$$. As this number can be large, output it modulo $$$998244353$$$.","['graphs', 'math']","[0, 0, 1, 1, 0, 0, 0, 0]"618"Sayaka Saeki is a member of the student council, which has $$$n$$$ other members (excluding Sayaka). The $$$i$$$-th member has a height of $$$a_i$$$ millimeters.It's the end of the school year and Sayaka wants to take a picture of all other members of the student council. Being the hard-working and perfectionist girl as she is, she wants to arrange all the members in a line such that the amount of photogenic consecutive pairs of members is as large as possible.A pair of two consecutive members $$$u$$$ and $$$v$$$ on a line is considered photogenic if their average height is an integer, i.e. $$$\frac{a_u + a_v}{2}$$$ is an integer.Help Sayaka arrange the other members to maximize the number of photogenic consecutive pairs.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"619"To stay woke and attentive during classes, Karen needs some coffee!  Karen, a coffee aficionado, wants to know the optimal temperature for brewing the perfect cup of coffee. Indeed, she has spent some time reading several recipe books, including the universally acclaimed ""The Art of the Covfefe"".She knows n coffee recipes. The i-th recipe suggests that coffee should be brewed between li and ri degrees, inclusive, to achieve the optimal taste.Karen thinks that a temperature is admissible if at least k recipes recommend it.Karen has a rather fickle mind, and so she asks q questions. In each question, given that she only wants to prepare coffee with a temperature between a and b, inclusive, can you tell her how many admissible integer temperatures fall within the range?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"620"You are given $$$n$$$ arrays $$$a_1$$$, $$$a_2$$$, ..., $$$a_n$$$; each array consists of exactly $$$m$$$ integers. We denote the $$$y$$$-th element of the $$$x$$$-th array as $$$a_{x, y}$$$.You have to choose two arrays $$$a_i$$$ and $$$a_j$$$ ($$$1 \le i, j \le n$$$, it is possible that $$$i = j$$$). After that, you will obtain a new array $$$b$$$ consisting of $$$m$$$ integers, such that for every $$$k \in [1, m]$$$ $$$b_k = \max(a_{i, k}, a_{j, k})$$$.Your goal is to choose $$$i$$$ and $$$j$$$ so that the value of $$$\min \limits_{k = 1}^{m} b_k$$$ is maximum possible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"621"Ivan has an array consisting of n elements. Each of the elements is an integer from 1 to n.Recently Ivan learned about permutations and their lexicographical order. Now he wants to change (replace) minimum number of elements in his array in such a way that his array becomes a permutation (i.e. each of the integers from 1 to n was encountered in his array exactly once). If there are multiple ways to do it he wants to find the lexicographically minimal permutation among them.Thus minimizing the number of changes has the first priority, lexicographical minimizing has the second priority.In order to determine which of the two permutations is lexicographically smaller, we compare their first elements. If they are equal — compare the second, and so on. If we have two permutations x and y, then x is lexicographically smaller if xi < yi, where i is the first index in which the permutations x and y differ.Determine the array Ivan will obtain after performing all the changes.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"622"A card pyramid of height $$$1$$$ is constructed by resting two cards against each other. For $$$h>1$$$, a card pyramid of height $$$h$$$ is constructed by placing a card pyramid of height $$$h-1$$$ onto a base. A base consists of $$$h$$$ pyramids of height $$$1$$$, and $$$h-1$$$ cards on top. For example, card pyramids of heights $$$1$$$, $$$2$$$, and $$$3$$$ look as follows:  You start with $$$n$$$ cards and build the tallest pyramid that you can. If there are some cards remaining, you build the tallest pyramid possible with the remaining cards. You repeat this process until it is impossible to build another pyramid. In the end, how many pyramids will you have constructed?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"623"Consider a table G of size n × m such that G(i, j) = GCD(i, j) for all 1 ≤ i ≤ n, 1 ≤ j ≤ m. GCD(a, b) is the greatest common divisor of numbers a and b.You have a sequence of positive integer numbers a1, a2, ..., ak. We say that this sequence occurs in table G if it coincides with consecutive elements in some row, starting from some position. More formally, such numbers 1 ≤ i ≤ n and 1 ≤ j ≤ m - k + 1 should exist that G(i, j + l - 1) = al for all 1 ≤ l ≤ k.Determine if the sequence a occurs in table G.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"624"Dima liked the present he got from Inna very much. He liked the present he got from Seryozha even more. Dima felt so grateful to Inna about the present that he decided to buy her n hares. Inna was very happy. She lined up the hares in a row, numbered them from 1 to n from left to right and started feeding them with carrots. Inna was determined to feed each hare exactly once. But in what order should she feed them?Inna noticed that each hare radiates joy when she feeds it. And the joy of the specific hare depends on whether Inna fed its adjacent hares before feeding it. Inna knows how much joy a hare radiates if it eats when either both of his adjacent hares are hungry, or one of the adjacent hares is full (that is, has been fed), or both of the adjacent hares are full. Please note that hares number 1 and n don't have a left and a right-adjacent hare correspondingly, so they can never have two full adjacent hares.Help Inna maximize the total joy the hares radiate. :)",[],"[0, 0, 0, 0, 0, 0, 0, 0]"625"Apart from plush toys, Imp is a huge fan of little yellow birds!  To summon birds, Imp needs strong magic. There are n trees in a row on an alley in a park, there is a nest on each of the trees. In the i-th nest there are ci birds; to summon one bird from this nest Imp needs to stay under this tree and it costs him costi points of mana. However, for each bird summoned, Imp increases his mana capacity by B points. Imp summons birds one by one, he can summon any number from 0 to ci birds from the i-th nest. Initially Imp stands under the first tree and has W points of mana, and his mana capacity equals W as well. He can only go forward, and each time he moves from a tree to the next one, he restores X points of mana (but it can't exceed his current mana capacity). Moving only forward, what is the maximum number of birds Imp can summon?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"626"'Twas the night before Christmas, and Santa's frantically setting up his new Christmas tree! There are $$$n$$$ nodes in the tree, connected by $$$n-1$$$ edges. On each edge of the tree, there's a set of Christmas lights, which can be represented by an integer in binary representation.  He has $$$m$$$ elves come over and admire his tree. Each elf is assigned two nodes, $$$a$$$ and $$$b$$$, and that elf looks at all lights on the simple path between the two nodes. After this, the elf's favorite number becomes the bitwise XOR of the values of the lights on the edges in that path.However, the North Pole has been recovering from a nasty bout of flu. Because of this, Santa forgot some of the configurations of lights he had put on the tree, and he has already left the North Pole! Fortunately, the elves came to the rescue, and each one told Santa what pair of nodes he was assigned $$$(a_i, b_i)$$$, as well as the parity of the number of set bits in his favorite number. In other words, he remembers whether the number of $$$1$$$'s when his favorite number is written in binary is odd or even.Help Santa determine if it's possible that the memories are consistent, and if it is, remember what his tree looked like, and maybe you'll go down in history!","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"627"In a medieval kingdom, the economic crisis is raging. Milk drops fall, Economic indicators are deteriorating every day, money from the treasury disappear. To remedy the situation, King Charles Sunnyface decided make his n sons-princes marry the brides with as big dowry as possible.In search of candidates, the king asked neighboring kingdoms, and after a while several delegations arrived with m unmarried princesses. Receiving guests, Karl learned that the dowry of the i th princess is wi of golden coins. Although the action takes place in the Middle Ages, progressive ideas are widespread in society, according to which no one can force a princess to marry a prince whom she does not like. Therefore, each princess has an opportunity to choose two princes, for each of which she is ready to become a wife. The princes were less fortunate, they will obey the will of their father in the matter of choosing a bride.Knowing the value of the dowry and the preferences of each princess, Charles wants to play weddings in such a way that the total dowry of the brides of all his sons would be as great as possible. At the same time to marry all the princes or princesses is not necessary. Each prince can marry no more than one princess, and vice versa, each princess can marry no more than one prince.Help the king to organize the marriage of his sons in the most profitable way for the treasury.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"628"One day Ms Swan bought an orange in a shop. The orange consisted of n·k segments, numbered with integers from 1 to n·k. There were k children waiting for Ms Swan at home. The children have recently learned about the orange and they decided to divide it between them. For that each child took a piece of paper and wrote the number of the segment that he would like to get: the i-th (1 ≤ i ≤ k) child wrote the number ai (1 ≤ ai ≤ n·k). All numbers ai accidentally turned out to be different.Now the children wonder, how to divide the orange so as to meet these conditions:  each child gets exactly n orange segments;  the i-th child gets the segment with number ai for sure;  no segment goes to two children simultaneously. Help the children, divide the orange and fulfill the requirements, described above.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"629"The king of Berland organizes a ball! $$$n$$$ pair are invited to the ball, they are numbered from $$$1$$$ to $$$n$$$. Each pair consists of one man and one woman. Each dancer (either man or woman) has a monochrome costume. The color of each costume is represented by an integer from $$$1$$$ to $$$k$$$, inclusive.Let $$$b_i$$$ be the color of the man's costume and $$$g_i$$$ be the color of the woman's costume in the $$$i$$$-th pair. You have to choose a color for each dancer's costume (i.e. values $$$b_1, b_2, \dots, b_n$$$ and $$$g_1, g_2, \dots g_n$$$) in such a way that:  for every $$$i$$$: $$$b_i$$$ and $$$g_i$$$ are integers between $$$1$$$ and $$$k$$$, inclusive;  there are no two completely identical pairs, i.e. no two indices $$$i, j$$$ ($$$i \ne j$$$) such that $$$b_i = b_j$$$ and $$$g_i = g_j$$$ at the same time;  there is no pair such that the color of the man's costume is the same as the color of the woman's costume in this pair, i.e. $$$b_i \ne g_i$$$ for every $$$i$$$;  for each two consecutive (adjacent) pairs both man's costume colors and woman's costume colors differ, i.e. for every $$$i$$$ from $$$1$$$ to $$$n-1$$$ the conditions $$$b_i \ne b_{i + 1}$$$ and $$$g_i \ne g_{i + 1}$$$ hold. Let's take a look at the examples of bad and good color choosing (for $$$n=4$$$ and $$$k=3$$$, man is the first in a pair and woman is the second):Bad color choosing:   $$$(1, 2)$$$, $$$(2, 3)$$$, $$$(3, 2)$$$, $$$(1, 2)$$$ — contradiction with the second rule (there are equal pairs);  $$$(2, 3)$$$, $$$(1, 1)$$$, $$$(3, 2)$$$, $$$(1, 3)$$$ — contradiction with the third rule (there is a pair with costumes of the same color);  $$$(1, 2)$$$, $$$(2, 3)$$$, $$$(1, 3)$$$, $$$(2, 1)$$$ — contradiction with the fourth rule (there are two consecutive pairs such that colors of costumes of men/women are the same). Good color choosing:   $$$(1, 2)$$$, $$$(2, 1)$$$, $$$(1, 3)$$$, $$$(3, 1)$$$;  $$$(1, 2)$$$, $$$(3, 1)$$$, $$$(2, 3)$$$, $$$(3, 2)$$$;  $$$(3, 1)$$$, $$$(1, 2)$$$, $$$(2, 3)$$$, $$$(3, 2)$$$. You have to find any suitable color choosing or say that no suitable choosing exists.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"630"Let's call some positive integer classy if its decimal representation contains no more than $$$3$$$ non-zero digits. For example, numbers $$$4$$$, $$$200000$$$, $$$10203$$$ are classy and numbers $$$4231$$$, $$$102306$$$, $$$7277420000$$$ are not.You are given a segment $$$[L; R]$$$. Count the number of classy integers $$$x$$$ such that $$$L \le x \le R$$$.Each testcase contains several segments, for each of them you are required to solve the problem separately.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"631"Polycarp has come up with a new game to play with you. He calls it ""A missing bigram"".A bigram of a word is a sequence of two adjacent letters in it.For example, word ""abbaaba"" contains bigrams ""ab"", ""bb"", ""ba"", ""aa"", ""ab"" and ""ba"".The game goes as follows. First, Polycarp comes up with a word, consisting only of lowercase letters 'a' and 'b'. Then, he writes down all its bigrams on a whiteboard in the same order as they appear in the word. After that, he wipes one of them off the whiteboard.Finally, Polycarp invites you to guess what the word that he has come up with was.Your goal is to find any word such that it's possible to write down all its bigrams and remove one of them, so that the resulting sequence of bigrams is the same as the one Polycarp ended up with.The tests are generated in such a way that the answer exists. If there are multiple answers, you can print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"632"Polycarp has a strict daily schedule. He has n alarms set for each day, and the i-th alarm rings each day at the same time during exactly one minute.Determine the longest time segment when Polycarp can sleep, i. e. no alarm rings in that period. It is possible that Polycarp begins to sleep in one day, and wakes up in another.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"633"You are given a directed graph consisting of n vertices and m edges (each edge is directed, so it can be traversed in only one direction). You are allowed to remove at most one edge from it.Can you make this graph acyclic by removing at most one edge from it? A directed graph is called acyclic iff it doesn't contain any cycle (a non-empty path that starts and ends in the same vertex).",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"634" — Hey folks, how do you like this problem?— That'll do it. BThero is a powerful magician. He has got $$$n$$$ piles of candies, the $$$i$$$-th pile initially contains $$$a_i$$$ candies. BThero can cast a copy-paste spell as follows:   He chooses two piles $$$(i, j)$$$ such that $$$1 \le i, j \le n$$$ and $$$i \ne j$$$.  All candies from pile $$$i$$$ are copied into pile $$$j$$$. Formally, the operation $$$a_j := a_j + a_i$$$ is performed. BThero can cast this spell any number of times he wants to — but unfortunately, if some pile contains strictly more than $$$k$$$ candies, he loses his magic power. What is the maximum number of times BThero can cast the spell without losing his power?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"635"Harry Potter and He-Who-Must-Not-Be-Named engaged in a fight to the death once again. This time they are located at opposite ends of the corridor of length l. Two opponents simultaneously charge a deadly spell in the enemy. We know that the impulse of Harry's magic spell flies at a speed of p meters per second, and the impulse of You-Know-Who's magic spell flies at a speed of q meters per second.The impulses are moving through the corridor toward each other, and at the time of the collision they turn round and fly back to those who cast them without changing their original speeds. Then, as soon as the impulse gets back to it's caster, the wizard reflects it and sends again towards the enemy, without changing the original speed of the impulse.Since Harry has perfectly mastered the basics of magic, he knows that after the second collision both impulses will disappear, and a powerful explosion will occur exactly in the place of their collision. However, the young wizard isn't good at math, so he asks you to calculate the distance from his position to the place of the second meeting of the spell impulses, provided that the opponents do not change positions during the whole fight.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"636"Petya and Gena play a very interesting game ""Put a Knight!"" on a chessboard n × n in size. In this game they take turns to put chess pieces called ""knights"" on the board so that no two knights could threat each other. A knight located in square (r, c) can threat squares (r - 1, c + 2), (r - 1, c - 2), (r + 1, c + 2), (r + 1, c - 2), (r - 2, c + 1), (r - 2, c - 1), (r + 2, c + 1) and (r + 2, c - 1) (some of the squares may be located outside the chessboard). The player who can't put a new knight during his move loses. Determine which player wins considering that both players play optimally well and Petya starts.","['games', 'math']","[1, 0, 0, 1, 0, 0, 0, 0]"637"Bear Limak examines a social network. Its main functionality is that two members can become friends (then they can talk with each other and share funny pictures).There are n members, numbered 1 through n. m pairs of members are friends. Of course, a member can't be a friend with themselves.Let A-B denote that members A and B are friends. Limak thinks that a network is reasonable if and only if the following condition is satisfied: For every three distinct members (X, Y, Z), if X-Y and Y-Z then also X-Z.For example: if Alan and Bob are friends, and Bob and Ciri are friends, then Alan and Ciri should be friends as well.Can you help Limak and check if the network is reasonable? Print ""YES"" or ""NO"" accordingly, without the quotes.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"638"This is the easy version of the problem. The only difference is that in this version $$$k = 0$$$.There is an array $$$a_1, a_2, \ldots, a_n$$$ of $$$n$$$ positive integers. You should divide it into a minimal number of continuous segments, such that in each segment there are no two numbers (on different positions), whose product is a perfect square.Moreover, it is allowed to do at most $$$k$$$ such operations before the division: choose a number in the array and change its value to any positive integer. But in this version $$$k = 0$$$, so it is not important.What is the minimum number of continuous segments you should use if you will make changes optimally?","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"639"You are given a permutation $$$p_1, p_2, \dots, p_n$$$. Then, an undirected graph is constructed in the following way: add an edge between vertices $$$i$$$, $$$j$$$ such that $$$i < j$$$ if and only if $$$p_i > p_j$$$. Your task is to count the number of connected components in this graph.Two vertices $$$u$$$ and $$$v$$$ belong to the same connected component if and only if there is at least one path along edges connecting $$$u$$$ and $$$v$$$.A permutation is an array consisting of $$$n$$$ distinct integers from $$$1$$$ to $$$n$$$ in arbitrary order. For example, $$$[2,3,1,5,4]$$$ is a permutation, but $$$[1,2,2]$$$ is not a permutation ($$$2$$$ appears twice in the array) and $$$[1,3,4]$$$ is also not a permutation ($$$n=3$$$ but there is $$$4$$$ in the array).","['graphs', 'math']","[0, 0, 1, 1, 0, 0, 0, 0]"640"You are given an array $$$a$$$ of length $$$n$$$. We define the equality of the array as the number of indices $$$1 \le i \le n - 1$$$ such that $$$a_i = a_{i + 1}$$$. We are allowed to do the following operation:  Select two integers $$$i$$$ and $$$x$$$ such that $$$1 \le i \le n - 1$$$ and $$$1 \le x \le 10^9$$$. Then, set $$$a_i$$$ and $$$a_{i + 1}$$$ to be equal to $$$x$$$. Find the minimum number of operations needed such that the equality of the array is less than or equal to $$$1$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"641"Berland National Library has recently been built in the capital of Berland. In addition, in the library you can take any of the collected works of Berland leaders, the library has a reading room.Today was the pilot launch of an automated reading room visitors' accounting system! The scanner of the system is installed at the entrance to the reading room. It records the events of the form ""reader entered room"", ""reader left room"". Every reader is assigned a registration number during the registration procedure at the library — it's a unique integer from 1 to 106. Thus, the system logs events of two forms:  ""+ ri"" — the reader with registration number ri entered the room;  ""- ri"" — the reader with registration number ri left the room. The first launch of the system was a success, it functioned for some period of time, and, at the time of its launch and at the time of its shutdown, the reading room may already have visitors.Significant funds of the budget of Berland have been spent on the design and installation of the system. Therefore, some of the citizens of the capital now demand to explain the need for this system and the benefits that its implementation will bring. Now, the developers of the system need to urgently come up with reasons for its existence.Help the system developers to find the minimum possible capacity of the reading room (in visitors) using the log of the system available to you.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"642Think of New York as a rectangular grid consisting of N vertical avenues numerated from 1 to N and M horizontal streets numerated 1 to M. C friends are staying at C hotels located at some street-avenue crossings. They are going to celebrate birthday of one of them in the one of H restaurants also located at some street-avenue crossings. They also want that the maximum distance covered by one of them while traveling to the restaurant to be minimum possible. Help friends choose optimal restaurant for a celebration.Suppose that the distance between neighboring crossings are all the same equal to one kilometer.,['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"643"Polycarpus has n friends in Tarasov city. Polycarpus knows phone numbers of all his friends: they are strings s1, s2, ..., sn. All these strings consist only of digits and have the same length. Once Polycarpus needed to figure out Tarasov city phone code. He assumed that the phone code of the city is the longest common prefix of all phone numbers of his friends. In other words, it is the longest string c which is a prefix (the beginning) of each si for all i (1 ≤ i ≤ n). Help Polycarpus determine the length of the city phone code. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"644"Berland is going through tough times — the dirt price has dropped and that is a blow to the country's economy. Everybody knows that Berland is the top world dirt exporter!The President of Berland was forced to leave only k of the currently existing n subway stations.The subway stations are located on a straight line one after another, the trains consecutively visit the stations as they move. You can assume that the stations are on the Ox axis, the i-th station is at point with coordinate xi. In such case the distance between stations i and j is calculated by a simple formula |xi - xj|.Currently, the Ministry of Transport is choosing which stations to close and which ones to leave. Obviously, the residents of the capital won't be too enthusiastic about the innovation, so it was decided to show the best side to the people. The Ministry of Transport wants to choose such k stations that minimize the average commute time in the subway!Assuming that the train speed is constant (it is a fixed value), the average commute time in the subway is calculated as the sum of pairwise distances between stations, divided by the number of pairs (that is ) and divided by the speed of the train.Help the Minister of Transport to solve this difficult problem. Write a program that, given the location of the stations selects such k stations that the average commute time in the subway is minimized.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"645"In the town of Aalam-Aara (meaning the Light of the Earth), previously there was no crime, no criminals but as the time progressed, sins started creeping into the hearts of once righteous people. Seeking solution to the problem, some of the elders found that as long as the corrupted part of population was kept away from the uncorrupted part, the crimes could be stopped. So, they are trying to set up a compound where they can keep the corrupted people. To ensure that the criminals don't escape the compound, a watchtower needs to be set up, so that they can be watched.Since the people of Aalam-Aara aren't very rich, they met up with a merchant from some rich town who agreed to sell them a land-plot which has already a straight line fence AB along which a few points are set up where they can put up a watchtower. Your task is to help them find out the number of points on that fence where the tower can be put up, so that all the criminals can be watched from there. Only one watchtower can be set up. A criminal is watchable from the watchtower if the line of visibility from the watchtower to him doesn't cross the plot-edges at any point between him and the tower i.e. as shown in figure 1 below, points X, Y, C and A are visible from point B but the points E and D are not.    Figure 1     Figure 2 Assume that the land plot is in the shape of a polygon and coordinate axes have been setup such that the fence AB is parallel to x-axis and the points where the watchtower can be set up are the integer points on the line. For example, in given figure 2, watchtower can be setup on any of five integer points on AB i.e. (4, 8), (5, 8), (6, 8), (7, 8) or (8, 8). You can assume that no three consecutive points are collinear and all the corner points other than A and B, lie towards same side of fence AB. The given polygon doesn't contain self-intersections.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"646"This is the easy version of the problem. The only difference is maximum value of $$$a_i$$$.Once in Kostomuksha Divan found an array $$$a$$$ consisting of positive integers. Now he wants to reorder the elements of $$$a$$$ to maximize the value of the following function: $$$$$$\sum_{i=1}^n \operatorname{gcd}(a_1, \, a_2, \, \dots, \, a_i),$$$$$$ where $$$\operatorname{gcd}(x_1, x_2, \ldots, x_k)$$$ denotes the greatest common divisor of integers $$$x_1, x_2, \ldots, x_k$$$, and $$$\operatorname{gcd}(x) = x$$$ for any integer $$$x$$$.Reordering elements of an array means changing the order of elements in the array arbitrary, or leaving the initial order.Of course, Divan can solve this problem. However, he found it interesting, so he decided to share it with you.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"647"You are given an array of $$$n$$$ non-negative integers $$$a_1, a_2, \ldots, a_n$$$. You can make the following operation: choose an integer $$$x \geq 2$$$ and replace each number of the array by the remainder when dividing that number by $$$x$$$, that is, for all $$$1 \leq i \leq n$$$ set $$$a_i$$$ to $$$a_i \bmod x$$$.Determine if it is possible to make all the elements of the array equal by applying the operation zero or more times.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"648"Polycarp is very careful. He even types numeric sequences carefully, unlike his classmates. If he sees a sequence without a space after the comma, with two spaces in a row, or when something else does not look neat, he rushes to correct it. For example, number sequence written like ""1,2 ,3,...,   10"" will be corrected to ""1, 2, 3, ..., 10"".In this task you are given a string s, which is composed by a concatination of terms, each of which may be:   a positive integer of an arbitrary length (leading zeroes are not allowed),  a ""comma"" symbol ("",""),  a ""space"" symbol ("" ""),  ""three dots"" (""..."", that is, exactly three points written one after another, also known as suspension points). Polycarp wants to add and remove spaces in the string s to ensure the following:   each comma is followed by exactly one space (if the comma is the last character in the string, this rule does not apply to it),  each ""three dots"" term is preceded by exactly one space (if the dots are at the beginning of the string, this rule does not apply to the term),  if two consecutive numbers were separated by spaces only (one or more), then exactly one of them should be left,  there should not be other spaces. Automate Polycarp's work and write a program that will process the given string s.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"649"Recently, Masha was presented with a chessboard with a height of $$$n$$$ and a width of $$$m$$$.The rows on the chessboard are numbered from $$$1$$$ to $$$n$$$ from bottom to top. The columns are numbered from $$$1$$$ to $$$m$$$ from left to right. Therefore, each cell can be specified with the coordinates $$$(x,y)$$$, where $$$x$$$ is the column number, and $$$y$$$ is the row number (do not mix up).Let us call a rectangle with coordinates $$$(a,b,c,d)$$$ a rectangle lower left point of which has coordinates $$$(a,b)$$$, and the upper right one — $$$(c,d)$$$.The chessboard is painted black and white as follows:   An example of a chessboard. Masha was very happy with the gift and, therefore, invited her friends Maxim and Denis to show off. The guys decided to make her a treat — they bought her a can of white and a can of black paint, so that if the old board deteriorates, it can be repainted. When they came to Masha, something unpleasant happened: first, Maxim went over the threshold and spilled white paint on the rectangle $$$(x_1,y_1,x_2,y_2)$$$. Then after him Denis spilled black paint on the rectangle $$$(x_3,y_3,x_4,y_4)$$$.To spill paint of color $$$color$$$ onto a certain rectangle means that all the cells that belong to the given rectangle become $$$color$$$. The cell dyeing is superimposed on each other (if at first some cell is spilled with white paint and then with black one, then its color will be black).Masha was shocked! She drove away from the guests and decided to find out how spoiled the gift was. For this, she needs to know the number of cells of white and black color. Help her find these numbers!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"650"Ridhiman challenged Ashish to find the maximum valued subsequence of an array $$$a$$$ of size $$$n$$$ consisting of positive integers. The value of a non-empty subsequence of $$$k$$$ elements of $$$a$$$ is defined as $$$\sum 2^i$$$ over all integers $$$i \ge 0$$$ such that at least $$$\max(1, k - 2)$$$ elements of the subsequence have the $$$i$$$-th bit set in their binary representation (value $$$x$$$ has the $$$i$$$-th bit set in its binary representation if $$$\lfloor \frac{x}{2^i} \rfloor \mod 2$$$ is equal to $$$1$$$). Recall that $$$b$$$ is a subsequence of $$$a$$$, if $$$b$$$ can be obtained by deleting some(possibly zero) elements from $$$a$$$.Help Ashish find the maximum value he can get by choosing some subsequence of $$$a$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"651"$$$n$$$ fishermen have just returned from a fishing vacation. The $$$i$$$-th fisherman has caught a fish of weight $$$a_i$$$.Fishermen are going to show off the fish they caught to each other. To do so, they firstly choose an order in which they show their fish (each fisherman shows his fish exactly once, so, formally, the order of showing fish is a permutation of integers from $$$1$$$ to $$$n$$$). Then they show the fish they caught according to the chosen order. When a fisherman shows his fish, he might either become happy, become sad, or stay content.Suppose a fisherman shows a fish of weight $$$x$$$, and the maximum weight of a previously shown fish is $$$y$$$ ($$$y = 0$$$ if that fisherman is the first to show his fish). Then:  if $$$x \ge 2y$$$, the fisherman becomes happy;  if $$$2x \le y$$$, the fisherman becomes sad;  if none of these two conditions is met, the fisherman stays content. Let's call an order in which the fishermen show their fish emotional if, after all fishermen show their fish according to this order, each fisherman becomes either happy or sad. Calculate the number of emotional orders modulo $$$998244353$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"652"This is an easier version of the next problem. In this version, $$$q = 0$$$.A sequence of integers is called nice if its elements are arranged in blocks like in $$$[3, 3, 3, 4, 1, 1]$$$. Formally, if two elements are equal, everything in between must also be equal.Let's define difficulty of a sequence as a minimum possible number of elements to change to get a nice sequence. However, if you change at least one element of value $$$x$$$ to value $$$y$$$, you must also change all other elements of value $$$x$$$ into $$$y$$$ as well. For example, for $$$[3, 3, 1, 3, 2, 1, 2]$$$ it isn't allowed to change first $$$1$$$ to $$$3$$$ and second $$$1$$$ to $$$2$$$. You need to leave $$$1$$$'s untouched or change them to the same value.You are given a sequence of integers $$$a_1, a_2, \ldots, a_n$$$ and $$$q$$$ updates.Each update is of form ""$$$i$$$ $$$x$$$"" — change $$$a_i$$$ to $$$x$$$. Updates are not independent (the change stays for the future).Print the difficulty of the initial sequence and of the sequence after every update.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"653"This is an interactive problem.Vladik has favorite game, in which he plays all his free time.Game field could be represented as n × m matrix which consists of cells of three types:   «.» — normal cell, player can visit it.  «F» — finish cell, player has to finish his way there to win. There is exactly one cell of this type.  «*» — dangerous cell, if player comes to this cell, he loses. Initially player is located in the left top cell with coordinates (1, 1). Player has access to 4 buttons ""U"", ""D"", ""L"", ""R"", each of them move player up, down, left and right directions respectively.But it’s not that easy! Sometimes friends play game and change functions of buttons. Function of buttons ""L"" and ""R"" could have been swapped, also functions of buttons ""U"" and ""D"" could have been swapped. Note that functions of buttons can be changed only at the beginning of the game.Help Vladik win the game!",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"654"You are given a tree consisting of $$$n$$$ vertices. A number is written on each vertex; the number on vertex $$$i$$$ is equal to $$$a_i$$$.Recall that a simple path is a path that visits each vertex at most once. Let the weight of the path be the bitwise XOR of the values written on vertices it consists of. Let's say that a tree is good if no simple path has weight $$$0$$$.You can apply the following operation any number of times (possibly, zero): select a vertex of the tree and replace the value written on it with an arbitrary positive integer. What is the minimum number of times you have to apply this operation in order to make the tree good?",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"655"This problem is a simplified version of D2, but it has significant differences, so read the whole statement.Polycarp has an array of $$$n$$$ ($$$n$$$ is even) integers $$$a_1, a_2, \dots, a_n$$$. Polycarp conceived of a positive integer $$$k$$$. After that, Polycarp began performing the following operations on the array: take an index $$$i$$$ ($$$1 \le i \le n$$$) and reduce the number $$$a_i$$$ by $$$k$$$.After Polycarp performed some (possibly zero) number of such operations, it turned out that all numbers in the array became the same. Find the maximum $$$k$$$ at which such a situation is possible, or print $$$-1$$$ if such a number can be arbitrarily large.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"656"Bob is preparing to pass IQ test. The most frequent task in this test is to find out which one of the given n numbers differs from the others. Bob observed that one number usually differs from the others in evenness. Help Bob — to check his answers, he needs a program that among the given n numbers finds one that is different in evenness.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"657"Polycarpus is an amateur programmer. Now he is analyzing a friend's program. He has already found there the function rangeIncrement(l, r), that adds 1 to each element of some array a for all indexes in the segment [l, r]. In other words, this function does the following: function rangeIncrement(l, r)    for i := l .. r do        a[i] = a[i] + 1Polycarpus knows the state of the array a after a series of function calls. He wants to determine the minimum number of function calls that lead to such state. In addition, he wants to find what function calls are needed in this case. It is guaranteed that the required number of calls does not exceed 105.Before calls of function rangeIncrement(l, r) all array elements equal zero.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"658"You are given a bracket sequence $$$s$$$ of length $$$n$$$, where $$$n$$$ is even (divisible by two). The string $$$s$$$ consists of $$$\frac{n}{2}$$$ opening brackets '(' and $$$\frac{n}{2}$$$ closing brackets ')'.In one move, you can choose exactly one bracket and move it to the beginning of the string or to the end of the string (i.e. you choose some index $$$i$$$, remove the $$$i$$$-th character of $$$s$$$ and insert it before or after all remaining characters of $$$s$$$).Your task is to find the minimum number of moves required to obtain regular bracket sequence from $$$s$$$. It can be proved that the answer always exists under the given constraints.Recall what the regular bracket sequence is:  ""()"" is regular bracket sequence;  if $$$s$$$ is regular bracket sequence then ""("" + $$$s$$$ + "")"" is regular bracket sequence;  if $$$s$$$ and $$$t$$$ are regular bracket sequences then $$$s$$$ + $$$t$$$ is regular bracket sequence. For example, ""()()"", ""(())()"", ""(())"" and ""()"" are regular bracket sequences, but "")("", ""()("" and "")))"" are not.You have to answer $$$t$$$ independent test cases.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"659"Implication is a function of two logical arguments, its value is false if and only if the value of the first argument is true and the value of the second argument is false. Implication is written by using character '', and the arguments and the result of the implication are written as '0' (false) and '1' (true). According to the definition of the implication:   When a logical expression contains multiple implications, then when there are no brackets, it will be calculated from left to fight. For example,. When there are brackets, we first calculate the expression in brackets. For example,.For the given logical expression  determine if it is possible to place there brackets so that the value of a logical expression is false. If it is possible, your task is to find such an arrangement of brackets.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"660"You work in a big office. It is a 9 floor building with an elevator that can accommodate up to 4 people. It is your responsibility to manage this elevator.Today you are late, so there are queues on some floors already. For each person you know the floor where he currently is and the floor he wants to reach. Also, you know the order in which people came to the elevator.According to the company's rules, if an employee comes to the elevator earlier than another one, he has to enter the elevator earlier too (even if these employees stay on different floors). Note that the employees are allowed to leave the elevator in arbitrary order.The elevator has two commands:   Go up or down one floor. The movement takes 1 second.  Open the doors on the current floor. During this operation all the employees who have reached their destination get out of the elevator. Then all the employees on the floor get in the elevator in the order they are queued up while it doesn't contradict the company's rules and there is enough space in the elevator. Each employee spends 1 second to get inside and outside the elevator. Initially the elevator is empty and is located on the floor 1.You are interested what is the minimum possible time you need to spend to deliver all the employees to their destination. It is not necessary to return the elevator to the floor 1.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"661"There are $$$n$$$ cities numbered from $$$1$$$ to $$$n$$$, and city $$$i$$$ has beauty $$$a_i$$$.A salesman wants to start at city $$$1$$$, visit every city exactly once, and return to city $$$1$$$.For all $$$i\ne j$$$, a flight from city $$$i$$$ to city $$$j$$$ costs $$$\max(c_i,a_j-a_i)$$$ dollars, where $$$c_i$$$ is the price floor enforced by city $$$i$$$. Note that there is no absolute value. Find the minimum total cost for the salesman to complete his trip.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"662"Timur's grandfather gifted him a chessboard to practice his chess skills. This chessboard is a grid $$$a$$$ with $$$n$$$ rows and $$$m$$$ columns with each cell having a non-negative integer written on it. Timur's challenge is to place a bishop on the board such that the sum of all cells attacked by the bishop is maximal. The bishop attacks in all directions diagonally, and there is no limit to the distance which the bishop can attack. Note that the cell on which the bishop is placed is also considered attacked. Help him find the maximal sum he can get.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"663"You are given an integer m as a product of integers a1, a2, ... an . Your task is to find the number of distinct decompositions of number m into the product of n ordered positive integers.Decomposition into n products, given in the input, must also be considered in the answer. As the answer can be very large, print it modulo 1000000007 (109 + 7).","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"664"You are given $$$n$$$ sticks with positive integral length $$$a_1, a_2, \ldots, a_n$$$.You can perform the following operation any number of times (possibly zero):   choose one stick, then either increase or decrease its length by $$$1$$$. After each operation, all sticks should have positive lengths. What is the minimum number of operations that you have to perform such that it is possible to select three of the $$$n$$$ sticks and use them without breaking to form an equilateral triangle?An equilateral triangle is a triangle where all of its three sides have the same length.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"665"You are given a circular array with n elements. The elements are numbered from some element with values from 1 to n in clockwise order. The i-th cell contains the value ai. The robot Simba is in cell s.Each moment of time the robot is in some of the n cells (at the begin he is in s). In one turn the robot can write out the number written in current cell or move to the adjacent cell in clockwise or counterclockwise direction. To write out the number from the cell Simba doesn't spend any time, but to move to adjacent cell Simba spends one unit of time.Simba wants to write the number from each cell one time, so the numbers will be written in a non decreasing order. Find the least number of time units to write out all numbers.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"666"Cirno gave AquaMoon a chessboard of size $$$1 \times n$$$. Its cells are numbered with integers from $$$1$$$ to $$$n$$$ from left to right. In the beginning, some of the cells are occupied with at most one pawn, and other cells are unoccupied.In each operation, AquaMoon can choose a cell $$$i$$$ with a pawn, and do either of the following (if possible):   Move pawn from it to the $$$(i+2)$$$-th cell, if $$$i+2 \leq n$$$ and the $$$(i+1)$$$-th cell is occupied and the $$$(i+2)$$$-th cell is unoccupied.  Move pawn from it to the $$$(i-2)$$$-th cell, if $$$i-2 \geq 1$$$ and the $$$(i-1)$$$-th cell is occupied and the $$$(i-2)$$$-th cell is unoccupied. You are given an initial state of the chessboard. AquaMoon wants to count the number of states reachable from the initial state with some sequence of operations. But she is not good at programming. Can you help her? As the answer can be large find it modulo $$$998\,244\,353$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"667"Polycarp is wondering about buying a new computer, which costs $$$c$$$ tugriks. To do this, he wants to get a job as a programmer in a big company.There are $$$n$$$ positions in Polycarp's company, numbered starting from one. An employee in position $$$i$$$ earns $$$a[i]$$$ tugriks every day. The higher the position number, the more tugriks the employee receives. Initially, Polycarp gets a position with the number $$$1$$$ and has $$$0$$$ tugriks.Each day Polycarp can do one of two things:   If Polycarp is in the position of $$$x$$$, then he can earn $$$a[x]$$$ tugriks.  If Polycarp is in the position of $$$x$$$ ($$$x < n$$$) and has at least $$$b[x]$$$ tugriks, then he can spend $$$b[x]$$$ tugriks on an online course and move to the position $$$x+1$$$. For example, if $$$n=4$$$, $$$c=15$$$, $$$a=[1, 3, 10, 11]$$$, $$$b=[1, 2, 7]$$$, then Polycarp can act like this:   On the first day, Polycarp is in the $$$1$$$-st position and earns $$$1$$$ tugrik. Now he has $$$1$$$ tugrik;  On the second day, Polycarp is in the $$$1$$$-st position and move to the $$$2$$$-nd position. Now he has $$$0$$$ tugriks;  On the third day, Polycarp is in the $$$2$$$-nd position and earns $$$3$$$ tugriks. Now he has $$$3$$$ tugriks;  On the fourth day, Polycarp is in the $$$2$$$-nd position and is transferred to the $$$3$$$-rd position. Now he has $$$1$$$ tugriks;  On the fifth day, Polycarp is in the $$$3$$$-rd position and earns $$$10$$$ tugriks. Now he has $$$11$$$ tugriks;  On the sixth day, Polycarp is in the $$$3$$$-rd position and earns $$$10$$$ tugriks. Now he has $$$21$$$ tugriks;  Six days later, Polycarp can buy himself a new computer. Find the minimum number of days after which Polycarp will be able to buy himself a new computer.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"668"There are n pictures delivered for the new exhibition. The i-th painting has beauty ai. We know that a visitor becomes happy every time he passes from a painting to a more beautiful one.We are allowed to arranged pictures in any order. What is the maximum possible number of times the visitor may become happy while passing all pictures from first to last? In other words, we are allowed to rearrange elements of a in any order. What is the maximum possible number of indices i (1 ≤ i ≤ n - 1), such that ai + 1 > ai.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"669"You are given an array of $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$.You will perform $$$q$$$ operations. In the $$$i$$$-th operation, you have a symbol $$$s_i$$$ which is either ""<"" or "">"" and a number $$$x_i$$$.You make a new array $$$b$$$ such that $$$b_j = -a_j$$$ if $$$a_j s_i x_i$$$ and $$$b_j = a_j$$$ otherwise (i.e. if $$$s_i$$$ is '>', then all $$$a_j > x_i$$$ will be flipped). After doing all these replacements, $$$a$$$ is set to be $$$b$$$.You want to know what your final array looks like after all operations.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"670"A camera you have accidentally left in a desert has taken an interesting photo. The photo has a resolution of n pixels width, and each column of this photo is all white or all black. Thus, we can represent the photo as a sequence of n zeros and ones, where 0 means that the corresponding column is all white, and 1 means that the corresponding column is black.You think that this photo can contain a zebra. In this case the whole photo should consist of several (possibly, only one) alternating black and white stripes of equal width. For example, the photo [0, 0, 0, 1, 1, 1, 0, 0, 0] can be a photo of zebra, while the photo [0, 0, 0, 1, 1, 1, 1] can not, because the width of the black stripe is 3, while the width of the white stripe is 4. Can the given photo be a photo of zebra or not?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"671"Drazil likes heap very much. So he created a problem with heap:There is a max heap with a height $$$h$$$ implemented on the array. The details of this heap are the following:This heap contains exactly $$$2^h - 1$$$ distinct positive non-zero integers. All integers are distinct. These numbers are stored in the array $$$a$$$ indexed from $$$1$$$ to $$$2^h-1$$$. For any $$$1 < i < 2^h$$$, $$$a[i] < a[\left \lfloor{\frac{i}{2}}\right \rfloor]$$$.Now we want to reduce the height of this heap such that the height becomes $$$g$$$ with exactly $$$2^g-1$$$ numbers in heap. To reduce the height, we should perform the following action $$$2^h-2^g$$$ times:Choose an index $$$i$$$, which contains an element and call the following function $$$f$$$ in index $$$i$$$:Note that we suppose that if $$$a[i]=0$$$, then index $$$i$$$ don't contain an element.After all operations, the remaining $$$2^g-1$$$ element must be located in indices from $$$1$$$ to $$$2^g-1$$$. Now Drazil wonders what's the minimum possible sum of the remaining $$$2^g-1$$$ elements. Please find this sum and find a sequence of the function calls to achieve this value.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"672"Vova promised himself that he would never play computer games... But recently Firestorm — a well-known game developing company — published their newest game, World of Farcraft, and it became really popular. Of course, Vova started playing it.Now he tries to solve a quest. The task is to come to a settlement named Overcity and spread a rumor in it.Vova knows that there are n characters in Overcity. Some characters are friends to each other, and they share information they got. Also Vova knows that he can bribe each character so he or she starts spreading the rumor; i-th character wants ci gold in exchange for spreading the rumor. When a character hears the rumor, he tells it to all his friends, and they start spreading the rumor to their friends (for free), and so on.The quest is finished when all n characters know the rumor. What is the minimum amount of gold Vova needs to spend in order to finish the quest?Take a look at the notes if you think you haven't understood the problem completely.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"673"Everyone knows that long ago on the territory of present-day Berland there lived Bindian tribes. Their capital was surrounded by n hills, forming a circle. On each hill there was a watchman, who watched the neighbourhood day and night.In case of any danger the watchman could make a fire on the hill. One watchman could see the signal of another watchman, if on the circle arc connecting the two hills there was no hill higher than any of the two. As for any two hills there are two different circle arcs connecting them, the signal was seen if the above mentioned condition was satisfied on at least one of the arcs. For example, for any two neighbouring watchmen it is true that the signal of one will be seen by the other.An important characteristics of this watch system was the amount of pairs of watchmen able to see each other's signals. You are to find this amount by the given heights of the hills.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"674"You have been invited as a production process optimization specialist to some very large company. The company has $$$n$$$ machines at its factory, standing one behind another in the production chain. Each machine can be described in one of the following two ways: $$$(+,~a_i)$$$ or $$$(*,~a_i)$$$.If a workpiece with the value $$$x$$$ is supplied to the machine of kind $$$(+,~a_i)$$$, then the output workpiece has value $$$x + a_i$$$.If a workpiece with the value $$$x$$$ is supplied to the machine of kind $$$(*,~a_i)$$$, then the output workpiece has value $$$x \cdot a_i$$$.The whole production process is as follows. The workpiece with the value $$$1$$$ is supplied to the first machine, then the workpiece obtained after the operation of the first machine is supplied to the second machine, then the workpiece obtained after the operation of the second machine is supplied to the third machine, and so on. The company is not doing very well, so now the value of the resulting product does not exceed $$$2 \cdot 10^9$$$.The directors of the company are not satisfied with the efficiency of the production process and have given you a budget of $$$b$$$ coins to optimize it.To optimize production you can change the order of machines in the chain. Namely, by spending $$$p$$$ coins, you can take any machine of kind $$$(+,~a_i)$$$ and move it to any place in the chain without changing the order of other machines. Also, by spending $$$m$$$ coins, you can take any machine of kind $$$(*,~a_i)$$$ and move it to any place in the chain.What is the maximum value of the resulting product that can be achieved if the total cost of movements that are made should not exceed $$$b$$$ coins?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"675"Appleman and Toastman play a game. Initially Appleman gives one group of n numbers to the Toastman, then they start to complete the following tasks:  Each time Toastman gets a group of numbers, he sums up all the numbers and adds this sum to the score. Then he gives the group to the Appleman.  Each time Appleman gets a group consisting of a single number, he throws this group out. Each time Appleman gets a group consisting of more than one number, he splits the group into two non-empty groups (he can do it in any way) and gives each of them to Toastman. After guys complete all the tasks they look at the score value. What is the maximum possible value of score they can get?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"676"These days Arkady works as an air traffic controller at a large airport. He controls a runway which is usually used for landings only. Thus, he has a schedule of planes that are landing in the nearest future, each landing lasts $$$1$$$ minute.He was asked to insert one takeoff in the schedule. The takeoff takes $$$1$$$ minute itself, but for safety reasons there should be a time space between the takeoff and any landing of at least $$$s$$$ minutes from both sides.Find the earliest time when Arkady can insert the takeoff.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"677"There are $$$n$$$ pieces of cake on a line. The $$$i$$$-th piece of cake has weight $$$a_i$$$ ($$$1 \leq i \leq n$$$).The tastiness of the cake is the maximum total weight of two adjacent pieces of cake (i. e., $$$\max(a_1+a_2,\, a_2+a_3,\, \ldots,\, a_{n-1} + a_{n})$$$).You want to maximize the tastiness of the cake. You are allowed to do the following operation at most once (doing more operations would ruin the cake):   Choose a contiguous subsegment $$$a[l, r]$$$ of pieces of cake ($$$1 \leq l \leq r \leq n$$$), and reverse it. The subsegment $$$a[l, r]$$$ of the array $$$a$$$ is the sequence $$$a_l, a_{l+1}, \dots, a_r$$$.If you reverse it, the array will become $$$a_1, a_2, \dots, a_{l-2}, a_{l-1}, \underline{a_r}, \underline{a_{r-1}}, \underline{\dots}, \underline{a_{l+1}}, \underline{a_l}, a_{r+1}, a_{r+2}, \dots, a_{n-1}, a_n$$$.For example, if the weights are initially $$$[5, 2, 1, 4, 7, 3]$$$, you can reverse the subsegment $$$a[2, 5]$$$, getting $$$[5, \underline{7}, \underline{4}, \underline{1}, \underline{2}, 3]$$$. The tastiness of the cake is now $$$5 + 7 = 12$$$ (while before the operation the tastiness was $$$4+7=11$$$).Find the maximum tastiness of the cake after doing the operation at most once.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"678"ZS the Coder and Chris the Baboon has explored Udayland for quite some time. They realize that it consists of n towns numbered from 1 to n. There are n directed roads in the Udayland. i-th of them goes from town i to some other town ai (ai ≠ i). ZS the Coder can flip the direction of any road in Udayland, i.e. if it goes from town A to town B before the flip, it will go from town B to town A after.ZS the Coder considers the roads in the Udayland confusing, if there is a sequence of distinct towns A1, A2, ..., Ak (k > 1) such that for every 1 ≤ i < k there is a road from town Ai to town Ai + 1 and another road from town Ak to town A1. In other words, the roads are confusing if some of them form a directed cycle of some towns.Now ZS the Coder wonders how many sets of roads (there are 2n variants) in initial configuration can he choose to flip such that after flipping each road in the set exactly once, the resulting network will not be confusing.Note that it is allowed that after the flipping there are more than one directed road from some town and possibly some towns with no roads leading out of it, or multiple roads between any pair of cities.","['graphs', 'math']","[0, 0, 1, 1, 0, 0, 0, 0]"679"The main road in Bytecity is a straight line from south to north. Conveniently, there are coordinates measured in meters from the southernmost building in north direction.At some points on the road there are n friends, and i-th of them is standing at the point xi meters and can move with any speed no greater than vi meters per second in any of the two directions along the road: south or north.You are to compute the minimum time needed to gather all the n friends at some point on the road. Note that the point they meet at doesn't need to have integer coordinate. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"680"Madoka is a very strange girl, and therefore she suddenly wondered how many pairs of integers $$$(a, b)$$$ exist, where $$$1 \leq a, b \leq n$$$, for which $$$\frac{\operatorname{lcm}(a, b)}{\operatorname{gcd}(a, b)} \leq 3$$$.In this problem, $$$\operatorname{gcd}(a, b)$$$ denotes the greatest common divisor of the numbers $$$a$$$ and $$$b$$$, and $$$\operatorname{lcm}(a, b)$$$ denotes the smallest common multiple of the numbers $$$a$$$ and $$$b$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"681"Initially there was an array $$$a$$$ consisting of $$$n$$$ integers. Positions in it are numbered from $$$1$$$ to $$$n$$$.Exactly $$$q$$$ queries were performed on the array. During the $$$i$$$-th query some segment $$$(l_i, r_i)$$$ $$$(1 \le l_i \le r_i \le n)$$$ was selected and values of elements on positions from $$$l_i$$$ to $$$r_i$$$ inclusive got changed to $$$i$$$. The order of the queries couldn't be changed and all $$$q$$$ queries were applied. It is also known that every position from $$$1$$$ to $$$n$$$ got covered by at least one segment.We could have offered you the problem about checking if some given array (consisting of $$$n$$$ integers with values from $$$1$$$ to $$$q$$$) can be obtained by the aforementioned queries. However, we decided that it will come too easy for you.So the enhancement we introduced to it is the following. Some set of positions (possibly empty) in this array is selected and values of elements on these positions are set to $$$0$$$.Your task is to check if this array can be obtained by the aforementioned queries. Also if it can be obtained then restore this array.If there are multiple possible arrays then print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"682"Recently, a start up by two students of a state university of city F gained incredible popularity. Now it's time to start a new company. But what do we call it?The market analysts came up with a very smart plan: the name of the company should be identical to its reflection in a mirror! In other words, if we write out the name of the company on a piece of paper in a line (horizontally, from left to right) with large English letters, then put this piece of paper in front of the mirror, then the reflection of the name in the mirror should perfectly match the line written on the piece of paper.There are many suggestions for the company name, so coming up to the mirror with a piece of paper for each name wouldn't be sensible. The founders of the company decided to automatize this process. They asked you to write a program that can, given a word, determine whether the word is a 'mirror' word or not.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"683"String x is an anagram of string y, if we can rearrange the letters in string x and get exact string y. For example, strings ""DOG"" and ""GOD"" are anagrams, so are strings ""BABA"" and ""AABB"", but strings ""ABBAC"" and ""CAABA"" are not.You are given two strings s and t of the same length, consisting of uppercase English letters. You need to get the anagram of string t from string s. You are permitted to perform the replacing operation: every operation is replacing some character from the string s by any other character. Get the anagram of string t in the least number of replacing operations. If you can get multiple anagrams of string t in the least number of operations, get the lexicographically minimal one.The lexicographic order of strings is the familiar to us ""dictionary"" order. Formally, the string p of length n is lexicographically smaller than string q of the same length, if p1 = q1, p2 = q2, ..., pk - 1 = qk - 1, pk < qk for some k (1 ≤ k ≤ n). Here characters in the strings are numbered from 1. The characters of the strings are compared in the alphabetic order.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"684"The only difference between this problem and the hard version is the maximum number of questions.This is an interactive problem.There is a hidden integer $$$1 \le x \le n$$$ which you have to find. In order to find it you can ask at most $$$\mathbf{82}$$$ questions.In each question you can choose a non-empty integer set $$$S$$$ and ask if $$$x$$$ belongs to $$$S$$$ or not, after each question, if $$$x$$$ belongs to $$$S$$$, you'll receive ""YES"", otherwise ""NO"".But the problem is that not all answers are necessarily true (some of them are joking), it's just guaranteed that for each two consecutive questions, at least one of them is answered correctly.Additionally to the questions, you can make at most $$$2$$$ guesses for the answer $$$x$$$. Each time you make a guess, if you guess $$$x$$$ correctly, you receive "":)"" and your program should terminate, otherwise you'll receive "":("".As a part of the joking, we will not fix the value of $$$x$$$ in the beginning. Instead, it can change throughout the interaction as long as all the previous responses are valid as described above.Note that your answer guesses are always answered correctly. If you ask a question before and after a guess, at least one of these two questions is answered correctly, as normal.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"685"A country has n cities. Initially, there is no road in the country. One day, the king decides to construct some roads connecting pairs of cities. Roads can be traversed either way. He wants those roads to be constructed in such a way that it is possible to go from each city to any other city by traversing at most two roads. You are also given m pairs of cities — roads cannot be constructed between these pairs of cities.Your task is to construct the minimum number of roads that still satisfy the above conditions. The constraints will guarantee that this is always possible.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"686"Consider the insertion sort algorithm used to sort an integer sequence $$$[a_1, a_2, \ldots, a_n]$$$ of length $$$n$$$ in non-decreasing order.For each $$$i$$$ in order from $$$2$$$ to $$$n$$$, do the following. If $$$a_i \ge a_{i-1}$$$, do nothing and move on to the next value of $$$i$$$. Otherwise, find the smallest $$$j$$$ such that $$$a_i < a_j$$$, shift the elements on positions from $$$j$$$ to $$$i-1$$$ by one position to the right, and write down the initial value of $$$a_i$$$ to position $$$j$$$. In this case we'll say that we performed an insertion of an element from position $$$i$$$ to position $$$j$$$.It can be noticed that after processing any $$$i$$$, the prefix of the sequence $$$[a_1, a_2, \ldots, a_i]$$$ is sorted in non-decreasing order, therefore, the algorithm indeed sorts any sequence.For example, sorting $$$[4, 5, 3, 1, 3]$$$ proceeds as follows:   $$$i = 2$$$: $$$a_2 \ge a_1$$$, do nothing;  $$$i = 3$$$: $$$j = 1$$$, insert from position $$$3$$$ to position $$$1$$$: $$$[3, 4, 5, 1, 3]$$$;  $$$i = 4$$$: $$$j = 1$$$, insert from position $$$4$$$ to position $$$1$$$: $$$[1, 3, 4, 5, 3]$$$;  $$$i = 5$$$: $$$j = 3$$$, insert from position $$$5$$$ to position $$$3$$$: $$$[1, 3, 3, 4, 5]$$$. You are given an integer $$$n$$$ and a list of $$$m$$$ integer pairs $$$(x_i, y_i)$$$. We are interested in sequences such that if you sort them using the above algorithm, exactly $$$m$$$ insertions will be performed: first from position $$$x_1$$$ to position $$$y_1$$$, then from position $$$x_2$$$ to position $$$y_2$$$, ..., finally, from position $$$x_m$$$ to position $$$y_m$$$.How many sequences of length $$$n$$$ consisting of (not necessarily distinct) integers between $$$1$$$ and $$$n$$$, inclusive, satisfy the above condition? Print this number modulo $$$998\,244\,353$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"687"A magic island Geraldion, where Gerald lives, has its own currency system. It uses banknotes of several values. But the problem is, the system is not perfect and sometimes it happens that Geraldionians cannot express a certain sum of money with any set of banknotes. Of course, they can use any number of banknotes of each value. Such sum is called unfortunate. Gerald wondered: what is the minimum unfortunate sum?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"688"There are $$$n$$$ houses numbered from $$$1$$$ to $$$n$$$ on a circle. For each $$$1 \leq i \leq n - 1$$$, house $$$i$$$ and house $$$i + 1$$$ are neighbours; additionally, house $$$n$$$ and house $$$1$$$ are also neighbours.Initially, $$$m$$$ of these $$$n$$$ houses are infected by a deadly virus. Each morning, Cirno can choose a house which is uninfected and protect the house from being infected permanently.Every day, the following things happen in order:  Cirno chooses an uninfected house, and protect it permanently.  All uninfected, unprotected houses which have at least one infected neighbor become infected. Cirno wants to stop the virus from spreading. Find the minimum number of houses that will be infected in the end, if she optimally choose the houses to protect.Note that every day Cirno always chooses a house to protect before the virus spreads. Also, a protected house will not be infected forever.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"689"You are given two strings $$$x$$$ and $$$y$$$, both consist only of lowercase Latin letters. Let $$$|s|$$$ be the length of string $$$s$$$.Let's call a sequence $$$a$$$ a merging sequence if it consists of exactly $$$|x|$$$ zeros and exactly $$$|y|$$$ ones in some order.A merge $$$z$$$ is produced from a sequence $$$a$$$ by the following rules:   if $$$a_i=0$$$, then remove a letter from the beginning of $$$x$$$ and append it to the end of $$$z$$$;  if $$$a_i=1$$$, then remove a letter from the beginning of $$$y$$$ and append it to the end of $$$z$$$. Two merging sequences $$$a$$$ and $$$b$$$ are different if there is some position $$$i$$$ such that $$$a_i \neq b_i$$$.Let's call a string $$$z$$$ chaotic if for all $$$i$$$ from $$$2$$$ to $$$|z|$$$ $$$z_{i-1} \neq z_i$$$.Let $$$s[l,r]$$$ for some $$$1 \le l \le r \le |s|$$$ be a substring of consecutive letters of $$$s$$$, starting from position $$$l$$$ and ending at position $$$r$$$ inclusive.Let $$$f(l_1, r_1, l_2, r_2)$$$ be the number of different merging sequences of $$$x[l_1,r_1]$$$ and $$$y[l_2,r_2]$$$ that produce chaotic merges. Note that only non-empty substrings of $$$x$$$ and $$$y$$$ are considered.Calculate $$$\sum \limits_{1 \le l_1 \le r_1 \le |x| \\ 1 \le l_2 \le r_2 \le |y|} f(l_1, r_1, l_2, r_2)$$$. Output the answer modulo $$$998\,244\,353$$$.","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"690"Heidi got one brain, thumbs up! But the evening isn't over yet and one more challenge awaits our dauntless agent: after dinner, at precisely midnight, the N attendees love to play a very risky game...Every zombie gets a number ni (1 ≤ ni ≤ N) written on his forehead. Although no zombie can see his own number, he can see the numbers written on the foreheads of all N - 1 fellows. Note that not all numbers have to be unique (they can even all be the same). From this point on, no more communication between zombies is allowed. Observation is the only key to success. When the cuckoo clock strikes midnight, all attendees have to simultaneously guess the number on their own forehead. If at least one of them guesses his number correctly, all zombies survive and go home happily. On the other hand, if not a single attendee manages to guess his number correctly, all of them are doomed to die!Zombies aren't very bright creatures though, and Heidi has to act fast if she does not want to jeopardize her life. She has one single option: by performing some quick surgery on the brain she managed to get from the chest, she has the ability to remotely reprogram the decision-making strategy of all attendees for their upcoming midnight game! Can you suggest a sound strategy to Heidi which, given the rules of the game, ensures that at least one attendee will guess his own number correctly, for any possible sequence of numbers on the foreheads?Given a zombie's rank R and the N - 1 numbers ni on the other attendees' foreheads, your program will have to return the number that the zombie of rank R shall guess. Those answers define your strategy, and we will check if it is flawless or not.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"691"Brothers Fred and George Weasley once got into the sporting goods store and opened a box of Quidditch balls. After long and painful experiments they found out that the Golden Snitch is not enchanted at all. It is simply a programmed device. It always moves along the same trajectory, which is a polyline with vertices at the points (x0, y0, z0), (x1, y1, z1), ..., (xn, yn, zn). At the beginning of the game the snitch is positioned at the point (x0, y0, z0), and then moves along the polyline at the constant speed vs. The twins have not yet found out how the snitch behaves then. Nevertheless, they hope that the retrieved information will help Harry Potter and his team in the upcoming match against Slytherin. Harry Potter learned that at the beginning the game he will be at the point (Px, Py, Pz) and his super fast Nimbus 2011 broom allows him to move at the constant speed vp in any direction or remain idle. vp is not less than the speed of the snitch vs. Harry Potter, of course, wants to catch the snitch as soon as possible. Or, if catching the snitch while it is moving along the polyline is impossible, he wants to hurry the Weasley brothers with their experiments. Harry Potter catches the snitch at the time when they are at the same point. Help Harry.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"692"You are given $$$n$$$ points on the plane. The polygon formed from all the $$$n$$$ points is strictly convex, that is, the polygon is convex, and there are no three collinear points (i.e. lying in the same straight line). The points are numbered from $$$1$$$ to $$$n$$$, in clockwise order.We define the distance between two points $$$p_1 = (x_1, y_1)$$$ and $$$p_2 = (x_2, y_2)$$$ as their Manhattan distance: $$$$$$d(p_1, p_2) = |x_1 - x_2| + |y_1 - y_2|.$$$$$$Furthermore, we define the perimeter of a polygon, as the sum of Manhattan distances between all adjacent pairs of points on it; if the points on the polygon are ordered as $$$p_1, p_2, \ldots, p_k$$$ $$$(k \geq 3)$$$, then the perimeter of the polygon is $$$d(p_1, p_2) + d(p_2, p_3) + \ldots + d(p_k, p_1)$$$.For some parameter $$$k$$$, let's consider all the polygons that can be formed from the given set of points, having any $$$k$$$ vertices, such that the polygon is not self-intersecting. For each such polygon, let's consider its perimeter. Over all such perimeters, we define $$$f(k)$$$ to be the maximal perimeter.Please note, when checking whether a polygon is self-intersecting, that the edges of a polygon are still drawn as straight lines. For instance, in the following pictures:  In the middle polygon, the order of points ($$$p_1, p_3, p_2, p_4$$$) is not valid, since it is a self-intersecting polygon. The right polygon (whose edges resemble the Manhattan distance) has the same order and is not self-intersecting, but we consider edges as straight lines. The correct way to draw this polygon is ($$$p_1, p_2, p_3, p_4$$$), which is the left polygon.Your task is to compute $$$f(3), f(4), \ldots, f(n)$$$. In other words, find the maximum possible perimeter for each possible number of points (i.e. $$$3$$$ to $$$n$$$).",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"693"There is an undirected tree of $$$n$$$ vertices, connected by $$$n-1$$$ bidirectional edges. There is also a snake stuck inside of this tree. Its head is at vertex $$$a$$$ and its tail is at vertex $$$b$$$. The snake's body occupies all vertices on the unique simple path between $$$a$$$ and $$$b$$$.The snake wants to know if it can reverse itself  — that is, to move its head to where its tail started, and its tail to where its head started. Unfortunately, the snake's movements are restricted to the tree's structure.In an operation, the snake can move its head to an adjacent vertex not currently occupied by the snake. When it does this, the tail moves one vertex closer to the head, so that the length of the snake remains unchanged. Similarly, the snake can also move its tail to an adjacent vertex not currently occupied by the snake. When it does this, the head moves one unit closer to the tail.  Let's denote a snake position by $$$(h,t)$$$, where $$$h$$$ is the index of the vertex with the snake's head, $$$t$$$ is the index of the vertex with the snake's tail. This snake can reverse itself with the movements $$$(4,7)\to (5,1)\to (4,2)\to (1, 3)\to (7,2)\to (8,1)\to (7,4)$$$. Determine if it is possible to reverse the snake with some sequence of operations.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"694"Squirrel Liss loves nuts. There are n trees (numbered 1 to n from west to east) along a street and there is a delicious nut on the top of each tree. The height of the tree i is hi. Liss wants to eat all nuts.Now Liss is on the root of the tree with the number 1. In one second Liss can perform one of the following actions:  Walk up or down one unit on a tree.  Eat a nut on the top of the current tree.  Jump to the next tree. In this action the height of Liss doesn't change. More formally, when Liss is at height h of the tree i (1 ≤ i ≤ n - 1), she jumps to height h of the tree i + 1. This action can't be performed if h > hi + 1. Compute the minimal time (in seconds) required to eat all nuts.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"695"Vasily exited from a store and now he wants to recheck the total price of all purchases in his bill. The bill is a string in which the names of the purchases and their prices are printed in a row without any spaces. Check has the format ""name1price1name2price2...namenpricen"", where namei (name of the i-th purchase) is a non-empty string of length not more than 10, consisting of lowercase English letters, and pricei (the price of the i-th purchase) is a non-empty string, consisting of digits and dots (decimal points). It is possible that purchases with equal names have different prices.The price of each purchase is written in the following format. If the price is an integer number of dollars then cents are not written.Otherwise, after the number of dollars a dot (decimal point) is written followed by cents in a two-digit format (if number of cents is between 1 and 9 inclusively, there is a leading zero).Also, every three digits (from less significant to the most) in dollars are separated by dot (decimal point). No extra leading zeroes are allowed. The price always starts with a digit and ends with a digit.For example:  ""234"", ""1.544"", ""149.431.10"", ""0.99"" and ""123.05"" are valid prices,  "".333"", ""3.33.11"", ""12.00"", "".33"", ""0.1234"" and ""1.2"" are not valid. Write a program that will find the total price of all purchases in the given bill.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"696"You are given an integer $$$n$$$. In $$$1$$$ move, you can do one of the following actions:  erase any digit of the number (it's acceptable that the number before the operation has exactly one digit and after the operation, it is ""empty"");  add one digit to the right. The actions may be performed in any order any number of times.Note that if, after deleting some digit from a number, it will contain leading zeroes, they will not be deleted. E.g. if you delete from the number $$$301$$$ the digit $$$3$$$, the result is the number $$$01$$$ (not $$$1$$$).You need to perform the minimum number of actions to make the number any power of $$$2$$$ (i.e. there's an integer $$$k$$$ ($$$k \ge 0$$$) such that the resulting number is equal to $$$2^k$$$). The resulting number must not have leading zeroes.E.g. consider $$$n=1052$$$. The answer is equal to $$$2$$$. First, let's add to the right one digit $$$4$$$ (the result will be $$$10524$$$). Then let's erase the digit $$$5$$$, so the result will be $$$1024$$$ which is a power of $$$2$$$.E.g. consider $$$n=8888$$$. The answer is equal to $$$3$$$. Let's erase any of the digits $$$8$$$ three times. The result will be $$$8$$$ which is a power of $$$2$$$.","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"697"You are given $$$4n$$$ sticks, the length of the $$$i$$$-th stick is $$$a_i$$$.You have to create $$$n$$$ rectangles, each rectangle will consist of exactly $$$4$$$ sticks from the given set. The rectangle consists of four sides, opposite sides should have equal length and all angles in it should be right. Note that each stick can be used in only one rectangle. Each stick should be used as a side, you cannot break the stick or use it not to the full length.You want to all rectangles to have equal area. The area of the rectangle with sides $$$a$$$ and $$$b$$$ is $$$a \cdot b$$$.Your task is to say if it is possible to create exactly $$$n$$$ rectangles of equal area or not.You have to answer $$$q$$$ independent queries.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"698"Harry Potter has a difficult homework. Given a rectangular table, consisting of n × m cells. Each cell of the table contains the integer. Harry knows how to use two spells: the first spell change the sign of the integers in the selected row, the second — in the selected column. Harry's task is to make non-negative the sum of the numbers in each row and each column using these spells.Alone, the boy can not cope. Help the young magician!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"699"Vova plays a computer game known as Mages and Monsters. Vova's character is a mage. Though as he has just started, his character knows no spells.Vova's character can learn new spells during the game. Every spell is characterized by two values xi and yi — damage per second and mana cost per second, respectively. Vova doesn't have to use a spell for an integer amount of seconds. More formally, if he uses a spell with damage x and mana cost y for z seconds, then he will deal x·z damage and spend y·z mana (no rounding). If there is no mana left (mana amount is set in the start of the game and it remains the same at the beginning of every fight), then character won't be able to use any spells. It is prohibited to use multiple spells simultaneously.Also Vova can fight monsters. Every monster is characterized by two values tj and hj — monster kills Vova's character in tj seconds and has hj health points. Mana refills after every fight (or Vova's character revives with full mana reserve), so previous fights have no influence on further ones.Vova's character kills a monster, if he deals hj damage to it in no more than tj seconds using his spells (it is allowed to use more than one spell in a fight) and spending no more mana than he had at the beginning of the fight. If monster's health becomes zero exactly in tj seconds (it means that the monster and Vova's character kill each other at the same time), then Vova wins the fight.You have to write a program which can answer two types of queries:  1 x y — Vova's character learns new spell which deals x damage per second and costs y mana per second.  2 t h — Vova fights the monster which kills his character in t seconds and has h health points. Note that queries are given in a different form. Also remember that Vova's character knows no spells at the beginning of the game.For every query of second type you have to determine if Vova is able to win the fight with corresponding monster.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"700"Naman has two binary strings $$$s$$$ and $$$t$$$ of length $$$n$$$ (a binary string is a string which only consists of the characters ""0"" and ""1""). He wants to convert $$$s$$$ into $$$t$$$ using the following operation as few times as possible.In one operation, he can choose any subsequence of $$$s$$$ and rotate it clockwise once.For example, if $$$s = 1\textbf{1}101\textbf{00}$$$, he can choose a subsequence corresponding to indices ($$$1$$$-based) $$$\{2, 6, 7 \}$$$ and rotate them clockwise. The resulting string would then be $$$s = 1\textbf{0}101\textbf{10}$$$.A string $$$a$$$ is said to be a subsequence of string $$$b$$$ if $$$a$$$ can be obtained from $$$b$$$ by deleting some characters without changing the ordering of the remaining characters.To perform a clockwise rotation on a sequence $$$c$$$ of size $$$k$$$ is to perform an operation which sets $$$c_1:=c_k, c_2:=c_1, c_3:=c_2, \ldots, c_k:=c_{k-1}$$$ simultaneously.Determine the minimum number of operations Naman has to perform to convert $$$s$$$ into $$$t$$$ or say that it is impossible. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"701"The New Vasjuki village is stretched along the motorway and that's why every house on it is characterized by its shift relative to some fixed point — the xi coordinate. The village consists of n houses, the i-th house is located in the point with coordinates of xi.TELE3, a cellular communication provider planned to locate three base stations so as to provide every house in the village with cellular communication. The base station having power d located in the point t provides with communication all the houses on the segment [t - d, t + d] (including boundaries).To simplify the integration (and simply not to mix anything up) all the three stations are planned to possess the equal power of d. Which minimal value of d is enough to provide all the houses in the village with cellular communication.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"702"Dima and Inna love spending time together. The problem is, Seryozha isn't too enthusiastic to leave his room for some reason. But Dima and Inna love each other so much that they decided to get criminal...Dima constructed a trap graph. He shouted: ""Hey Seryozha, have a look at my cool graph!"" to get his roommate interested and kicked him into the first node.A trap graph is an undirected graph consisting of n nodes and m edges. For edge number k, Dima denoted a range of integers from lk to rk (lk ≤ rk). In order to get out of the trap graph, Seryozha initially (before starting his movements) should pick some integer (let's call it x), then Seryozha must go some way from the starting node with number 1 to the final node with number n. At that, Seryozha can go along edge k only if lk ≤ x ≤ rk.Seryozha is a mathematician. He defined the loyalty of some path from the 1-st node to the n-th one as the number of integers x, such that if he initially chooses one of them, he passes the whole path. Help Seryozha find the path of maximum loyalty and return to his room as quickly as possible!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"703"You are given a connected weighted undirected graph, consisting of $$$n$$$ vertices and $$$m$$$ edges.You are asked $$$k$$$ queries about it. Each query consists of a single integer $$$x$$$. For each query, you select a spanning tree in the graph. Let the weights of its edges be $$$w_1, w_2, \dots, w_{n-1}$$$. The cost of a spanning tree is $$$\sum \limits_{i=1}^{n-1} |w_i - x|$$$ (the sum of absolute differences between the weights and $$$x$$$). The answer to a query is the lowest cost of a spanning tree.The queries are given in a compressed format. The first $$$p$$$ $$$(1 \le p \le k)$$$ queries $$$q_1, q_2, \dots, q_p$$$ are provided explicitly. For queries from $$$p+1$$$ to $$$k$$$, $$$q_j = (q_{j-1} \cdot a + b) \mod c$$$.Print the xor of answers to all queries.","['graphs', 'math', 'trees']","[0, 0, 1, 1, 0, 0, 0, 1]"704"On the well-known testing system MathForces, a draw of $$$n$$$ rating units is arranged. The rating will be distributed according to the following algorithm: if $$$k$$$ participants take part in this event, then the $$$n$$$ rating is evenly distributed between them and rounded to the nearest lower integer, At the end of the drawing, an unused rating may remain — it is not given to any of the participants.For example, if $$$n = 5$$$ and $$$k = 3$$$, then each participant will recieve an $$$1$$$ rating unit, and also $$$2$$$ rating units will remain unused. If $$$n = 5$$$, and $$$k = 6$$$, then none of the participants will increase their rating.Vasya participates in this rating draw but does not have information on the total number of participants in this event. Therefore, he wants to know what different values of the rating increment are possible to get as a result of this draw and asks you for help.For example, if $$$n=5$$$, then the answer is equal to the sequence $$$0, 1, 2, 5$$$. Each of the sequence values (and only them) can be obtained as $$$\lfloor n/k \rfloor$$$ for some positive integer $$$k$$$ (where $$$\lfloor x \rfloor$$$ is the value of $$$x$$$ rounded down): $$$0 = \lfloor 5/7 \rfloor$$$, $$$1 = \lfloor 5/5 \rfloor$$$, $$$2 = \lfloor 5/2 \rfloor$$$, $$$5 = \lfloor 5/1 \rfloor$$$.Write a program that, for a given $$$n$$$, finds a sequence of all possible rating increments.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"705"This is an interactive problem. Don't forget to flush output after printing queries using cout.flush() or fflush(stdout) in C++ or similar functions in other programming languages.There are $$$n$$$ gift boxes in a row, numbered from $$$1$$$ to $$$n$$$ from left to right. It's known that exactly $$$k$$$ of them contain valuable gifts — other boxes contain just lucky stones. All boxes look the same and differ only in weight. All boxes with stones have the same weight and are strictly heavier than boxes with valuable items. But valuable gifts may be different, so the boxes with valuable items may have different weights.You can ask no more than $$$50$$$ queries (printing an answer doesn't count). By each query you can compare total weights of two non-intersecting subsets of boxes $$$a_1, a_2, \dots, a_{k_a}$$$ and $$$b_1, b_2, \dots, b_{k_b}$$$. In return you'll get one of four results:  FIRST, if subset $$$a_1, a_2, \dots, a_{k_a}$$$ is strictly heavier;  SECOND, if subset $$$b_1, b_2, \dots, b_{k_b}$$$ is strictly heavier;  EQUAL, if subsets have equal total weights;  WASTED, if the query is incorrect or the limit of queries is exceeded. Using such queries (or, maybe, intuition) find the box with a valuable gift with the minimum index.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"706You have a blackboard and initially only an odd number $$$x$$$ is written on it. Your goal is to write the number $$$1$$$ on the blackboard.You may write new numbers on the blackboard with the following two operations.   You may take two numbers (not necessarily distinct) already on the blackboard and write their sum on the blackboard. The two numbers you have chosen remain on the blackboard.  You may take two numbers (not necessarily distinct) already on the blackboard and write their bitwise XOR on the blackboard. The two numbers you have chosen remain on the blackboard.  Perform a sequence of operations such that at the end the number $$$1$$$ is on the blackboard.,"['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"707"Polycarp is practicing his problem solving skill. He has a list of $$$n$$$ problems with difficulties $$$a_1, a_2, \dots, a_n$$$, respectively. His plan is to practice for exactly $$$k$$$ days. Each day he has to solve at least one problem from his list. Polycarp solves the problems in the order they are given in his list, he cannot skip any problem from his list. He has to solve all $$$n$$$ problems in exactly $$$k$$$ days.Thus, each day Polycarp solves a contiguous sequence of (consecutive) problems from the start of the list. He can't skip problems or solve them multiple times. As a result, in $$$k$$$ days he will solve all the $$$n$$$ problems.The profit of the $$$j$$$-th day of Polycarp's practice is the maximum among all the difficulties of problems Polycarp solves during the $$$j$$$-th day (i.e. if he solves problems with indices from $$$l$$$ to $$$r$$$ during a day, then the profit of the day is $$$\max\limits_{l \le i \le r}a_i$$$). The total profit of his practice is the sum of the profits over all $$$k$$$ days of his practice.You want to help Polycarp to get the maximum possible total profit over all valid ways to solve problems. Your task is to distribute all $$$n$$$ problems between $$$k$$$ days satisfying the conditions above in such a way, that the total profit is maximum.For example, if $$$n = 8, k = 3$$$ and $$$a = [5, 4, 2, 6, 5, 1, 9, 2]$$$, one of the possible distributions with maximum total profit is: $$$[5, 4, 2], [6, 5], [1, 9, 2]$$$. Here the total profit equals $$$5 + 6 + 9 = 20$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"708"Recently, Dima met with Sasha in a philatelic store, and since then they are collecting coins together. Their favorite occupation is to sort collections of coins. Sasha likes having things in order, that is why he wants his coins to be arranged in a row in such a way that firstly come coins out of circulation, and then come coins still in circulation. For arranging coins Dima uses the following algorithm. One step of his algorithm looks like the following:  He looks through all the coins from left to right;  If he sees that the i-th coin is still in circulation, and (i + 1)-th coin is already out of circulation, he exchanges these two coins and continues watching coins from (i + 1)-th.  Dima repeats the procedure above until it happens that no two coins were exchanged during this procedure. Dima calls hardness of ordering the number of steps required for him according to the algorithm above to sort the sequence, e.g. the number of times he looks through the coins from the very beginning. For example, for the ordered sequence hardness of ordering equals one.Today Sasha invited Dima and proposed him a game. First he puts n coins in a row, all of them are out of circulation. Then Sasha chooses one of the coins out of circulation and replaces it with a coin in circulation for n times. During this process Sasha constantly asks Dima what is the hardness of ordering of the sequence. The task is more complicated because Dima should not touch the coins and he should determine hardness of ordering in his mind. Help Dima with this task. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"709"There are $$$n$$$ robbers at coordinates $$$(a_1, b_1)$$$, $$$(a_2, b_2)$$$, ..., $$$(a_n, b_n)$$$ and $$$m$$$ searchlight at coordinates $$$(c_1, d_1)$$$, $$$(c_2, d_2)$$$, ..., $$$(c_m, d_m)$$$. In one move you can move each robber to the right (increase $$$a_i$$$ of each robber by one) or move each robber up (increase $$$b_i$$$ of each robber by one). Note that you should either increase all $$$a_i$$$ or all $$$b_i$$$, you can't increase $$$a_i$$$ for some points and $$$b_i$$$ for some other points.Searchlight $$$j$$$ can see a robber $$$i$$$ if $$$a_i \leq c_j$$$ and $$$b_i \leq d_j$$$. A configuration of robbers is safe if no searchlight can see a robber (i.e. if there is no pair $$$i,j$$$ such that searchlight $$$j$$$ can see a robber $$$i$$$).What is the minimum number of moves you need to perform to reach a safe configuration?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"710"Let's call two numbers similar if their binary representations contain the same number of digits equal to $$$1$$$. For example:  $$$2$$$ and $$$4$$$ are similar (binary representations are $$$10$$$ and $$$100$$$);  $$$1337$$$ and $$$4213$$$ are similar (binary representations are $$$10100111001$$$ and $$$1000001110101$$$);  $$$3$$$ and $$$2$$$ are not similar (binary representations are $$$11$$$ and $$$10$$$);  $$$42$$$ and $$$13$$$ are similar (binary representations are $$$101010$$$ and $$$1101$$$). You are given an array of $$$n$$$ integers $$$a_1$$$, $$$a_2$$$, ..., $$$a_n$$$. You may choose a non-negative integer $$$x$$$, and then get another array of $$$n$$$ integers $$$b_1$$$, $$$b_2$$$, ..., $$$b_n$$$, where $$$b_i = a_i \oplus x$$$ ($$$\oplus$$$ denotes bitwise XOR).Is it possible to obtain an array $$$b$$$ where all numbers are similar to each other?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"711"Petya and Vasya arranged a game. The game runs by the following rules. Players have a directed graph consisting of n vertices and m edges. One of the vertices contains a chip. Initially the chip is located at vertex s. Players take turns moving the chip along some edge of the graph. Petya goes first. Player who can't move the chip loses. If the game lasts for 106 turns the draw is announced.Vasya was performing big laboratory work in ""Spelling and parts of speech"" at night before the game, so he fell asleep at the very beginning of the game. Petya decided to take the advantage of this situation and make both Petya's and Vasya's moves.Your task is to help Petya find out if he can win the game or at least draw a tie.","['games', 'graphs']","[1, 0, 1, 0, 0, 0, 0, 0]"712"Kuro has just learned about permutations and he is really excited to create a new permutation type. He has chosen $$$n$$$ distinct positive integers and put all of them in a set $$$S$$$. Now he defines a magical permutation to be: A permutation of integers from $$$0$$$ to $$$2^x - 1$$$, where $$$x$$$ is a non-negative integer.  The bitwise xor of any two consecutive elements in the permutation is an element in $$$S$$$.Since Kuro is really excited about magical permutations, he wants to create the longest magical permutation possible. In other words, he wants to find the largest non-negative integer $$$x$$$ such that there is a magical permutation of integers from $$$0$$$ to $$$2^x - 1$$$. Since he is a newbie in the subject, he wants you to help him find this value of $$$x$$$ and also the magical permutation for that $$$x$$$.","['graphs', 'math']","[0, 0, 1, 1, 0, 0, 0, 0]"713"There is a $$$k \times k$$$ grid, where $$$k$$$ is even. The square in row $$$r$$$ and column $$$c$$$ is denoted by $$$(r,c)$$$. Two squares $$$(r_1, c_1)$$$ and $$$(r_2, c_2)$$$ are considered adjacent if $$$\lvert r_1 - r_2 \rvert + \lvert c_1 - c_2 \rvert = 1$$$.An array of adjacent pairs of squares is called strong if it is possible to cut the grid along grid lines into two connected, congruent pieces so that each pair is part of the same piece. Two pieces are congruent if one can be matched with the other by translation, rotation, and reflection, or a combination of these.  The picture above represents the first test case. Arrows indicate pairs of squares, and the thick black line represents the cut. You are given an array $$$a$$$ of $$$n$$$ pairs of adjacent squares. Find the size of the largest strong subsequence of $$$a$$$. An array $$$p$$$ is a subsequence of an array $$$q$$$ if $$$p$$$ can be obtained from $$$q$$$ by deletion of several (possibly, zero or all) elements.","['geometry', 'graphs']","[0, 1, 1, 0, 0, 0, 0, 0]"714"Egor has a table of size $$$n \times m$$$, with lines numbered from $$$1$$$ to $$$n$$$ and columns numbered from $$$1$$$ to $$$m$$$. Each cell has a color that can be presented as an integer from $$$1$$$ to $$$10^5$$$.Let us denote the cell that lies in the intersection of the $$$r$$$-th row and the $$$c$$$-th column as $$$(r, c)$$$. We define the manhattan distance between two cells $$$(r_1, c_1)$$$ and $$$(r_2, c_2)$$$ as the length of a shortest path between them where each consecutive cells in the path must have a common side. The path can go through cells of any color. For example, in the table $$$3 \times 4$$$ the manhattan distance between $$$(1, 2)$$$ and $$$(3, 3)$$$ is $$$3$$$, one of the shortest paths is the following: $$$(1, 2) \to (2, 2) \to (2, 3) \to (3, 3)$$$. Egor decided to calculate the sum of manhattan distances between each pair of cells of the same color. Help him to calculate this sum.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"715"There is a given sequence of integers a1, a2, ..., an, where every number is from 1 to 3 inclusively. You have to replace the minimum number of numbers in it so that all the numbers in the sequence are equal to each other.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"716"A bracket sequence is a string containing only characters ""("" and "")"".A regular bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters ""1"" and ""+"" between the original characters of the sequence. For example, bracket sequences ""()()"", ""(())"" are regular (the resulting expressions are: ""(1)+(1)"", ""((1+1)+1)""), and "")("" and ""("" are not.You are given $$$n$$$ bracket sequences $$$s_1, s_2, \dots , s_n$$$. Calculate the number of pairs $$$i, j \, (1 \le i, j \le n)$$$ such that the bracket sequence $$$s_i + s_j$$$ is a regular bracket sequence. Operation $$$+$$$ means concatenation i.e. ""()("" + "")()"" = ""()()()"".If $$$s_i + s_j$$$ and $$$s_j + s_i$$$ are regular bracket sequences and $$$i \ne j$$$, then both pairs $$$(i, j)$$$ and $$$(j, i)$$$ must be counted in the answer. Also, if $$$s_i + s_i$$$ is a regular bracket sequence, the pair $$$(i, i)$$$ must be counted in the answer.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"717"Little penguin Polo adores strings. But most of all he adores strings of length n.One day he wanted to find a string that meets the following conditions:  The string consists of n lowercase English letters (that is, the string's length equals n), exactly k of these letters are distinct.  No two neighbouring letters of a string coincide; that is, if we represent a string as s = s1s2... sn, then the following inequality holds, si ≠ si + 1(1 ≤ i < n).  Among all strings that meet points 1 and 2, the required string is lexicographically smallest. Help him find such string or state that such string doesn't exist.String x = x1x2... xp is lexicographically less than string y = y1y2... yq, if either p < q and x1 = y1, x2 = y2, ... , xp = yp, or there is such number r (r < p, r < q), that x1 = y1, x2 = y2, ... , xr = yr and xr + 1 < yr + 1. The characters of the strings are compared by their ASCII codes.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"718"Dr. Moriarty is about to send a message to Sherlock Holmes. He has a string s. String p is called a substring of string s if you can read it starting from some position in the string s. For example, string ""aba"" has six substrings: ""a"", ""b"", ""a"", ""ab"", ""ba"", ""aba"".Dr. Moriarty plans to take string s and cut out some substring from it, let's call it t. Then he needs to change the substring t zero or more times. As a result, he should obtain a fixed string u (which is the string that should be sent to Sherlock Holmes). One change is defined as making one of the following actions:   Insert one letter to any end of the string.  Delete one letter from any end of the string.  Change one letter into any other one. Moriarty is very smart and after he chooses some substring t, he always makes the minimal number of changes to obtain u. Help Moriarty choose the best substring t from all substrings of the string s. The substring t should minimize the number of changes Moriarty should make to obtain the string u from it.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"719"Authors guessed an array $$$a$$$ consisting of $$$n$$$ integers; each integer is not less than $$$2$$$ and not greater than $$$2 \cdot 10^5$$$. You don't know the array $$$a$$$, but you know the array $$$b$$$ which is formed from it with the following sequence of operations:  Firstly, let the array $$$b$$$ be equal to the array $$$a$$$;  Secondly, for each $$$i$$$ from $$$1$$$ to $$$n$$$:   if $$$a_i$$$ is a prime number, then one integer $$$p_{a_i}$$$ is appended to array $$$b$$$, where $$$p$$$ is an infinite sequence of prime numbers ($$$2, 3, 5, \dots$$$);  otherwise (if $$$a_i$$$ is not a prime number), the greatest divisor of $$$a_i$$$ which is not equal to $$$a_i$$$ is appended to $$$b$$$;   Then the obtained array of length $$$2n$$$ is shuffled and given to you in the input. Here $$$p_{a_i}$$$ means the $$$a_i$$$-th prime number. The first prime $$$p_1 = 2$$$, the second one is $$$p_2 = 3$$$, and so on.Your task is to recover any suitable array $$$a$$$ that forms the given array $$$b$$$. It is guaranteed that the answer exists (so the array $$$b$$$ is obtained from some suitable array $$$a$$$). If there are multiple answers, you can print any.","['graphs', 'number theory']","[0, 0, 1, 0, 1, 0, 0, 0]"720"You are given a rooted tree, consisting of $$$n$$$ vertices. The vertices are numbered from $$$1$$$ to $$$n$$$, the root is the vertex $$$1$$$.You can perform the following operation at most $$$k$$$ times:   choose an edge $$$(v, u)$$$ of the tree such that $$$v$$$ is a parent of $$$u$$$;  remove the edge $$$(v, u)$$$;  add an edge $$$(1, u)$$$ (i. e. make $$$u$$$ with its subtree a child of the root). The height of a tree is the maximum depth of its vertices, and the depth of a vertex is the number of edges on the path from the root to it. For example, the depth of vertex $$$1$$$ is $$$0$$$, since it's the root, and the depth of all its children is $$$1$$$.What's the smallest height of the tree that can be achieved?","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"721"You are given a tree consisting of $$$n$$$ vertices. A number is written on each vertex; the number on vertex $$$i$$$ is equal to $$$a_i$$$.Let's denote the function $$$g(x, y)$$$ as the greatest common divisor of the numbers written on the vertices belonging to the simple path from vertex $$$x$$$ to vertex $$$y$$$ (including these two vertices). Also let's denote $$$dist(x, y)$$$ as the number of vertices on the simple path between vertices $$$x$$$ and $$$y$$$, including the endpoints. $$$dist(x, x) = 1$$$ for every vertex $$$x$$$.Your task is calculate the maximum value of $$$dist(x, y)$$$ among such pairs of vertices that $$$g(x, y) > 1$$$.","['number theory', 'trees']","[0, 0, 0, 0, 1, 0, 0, 1]"722"You have a string $$$s$$$ consisting of lowercase Latin alphabet letters. You can color some letters in colors from $$$1$$$ to $$$k$$$. It is not necessary to paint all the letters. But for each color, there must be a letter painted in that color.Then you can swap any two symbols painted in the same color as many times as you want. After that, $$$k$$$ strings will be created, $$$i$$$-th of them will contain all the characters colored in the color $$$i$$$, written in the order of their sequence in the string $$$s$$$.Your task is to color the characters of the string so that all the resulting $$$k$$$ strings are palindromes, and the length of the shortest of these $$$k$$$ strings is as large as possible.Read the note for the first test case of the example if you need a clarification.Recall that a string is a palindrome if it reads the same way both from left to right and from right to left. For example, the strings abacaba, cccc, z and dxd are palindromes, but the strings abab and aaabaa — are not.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"723"There are $$$n$$$ lanterns in a row. The lantern $$$i$$$ is placed in position $$$i$$$ and has power equal to $$$p_i$$$.Each lantern can be directed to illuminate either some lanterns to the left or some lanterns to the right. If the $$$i$$$-th lantern is turned to the left, it illuminates all such lanterns $$$j$$$ that $$$j \in [i - p_i, i - 1]$$$. Similarly, if it is turned to the right, it illuminates all such lanterns $$$j$$$ that $$$j \in [i + 1, i + p_i]$$$.Your goal is to choose a direction for each lantern so each lantern is illuminated by at least one other lantern, or report that it is impossible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"724"Kuroni isn't good at economics. So he decided to found a new financial pyramid called Antihype. It has the following rules:  You can join the pyramid for free and get $$$0$$$ coins.  If you are already a member of Antihype, you can invite your friend who is currently not a member of Antihype, and get a number of coins equal to your age (for each friend you invite). $$$n$$$ people have heard about Antihype recently, the $$$i$$$-th person's age is $$$a_i$$$. Some of them are friends, but friendship is a weird thing now: the $$$i$$$-th person is a friend of the $$$j$$$-th person if and only if $$$a_i \text{ AND } a_j = 0$$$, where $$$\text{AND}$$$ denotes the bitwise AND operation.Nobody among the $$$n$$$ people is a member of Antihype at the moment. They want to cooperate to join and invite each other to Antihype in a way that maximizes their combined gainings. Could you help them? ",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"725"Today Pari and Arya are playing a game called Remainders.Pari chooses two positive integer x and k, and tells Arya k but not x. Arya have to find the value . There are n ancient numbers c1, c2, ..., cn and Pari has to tell Arya  if Arya wants. Given k and the ancient values, tell us if Arya has a winning strategy independent of value of x or not. Formally, is it true that Arya can understand the value  for any positive integer x?Note, that  means the remainder of x after dividing it by y.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"726"A bracket sequence is a string, containing only characters ""("", "")"", ""["" and ""]"".A correct bracket sequence is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters ""1"" and ""+"" between the original characters of the sequence. For example, bracket sequences ""()[]"", ""([])"" are correct (the resulting expressions are: ""(1)+[1]"", ""([1+1]+1)""), and ""]("" and ""["" are not. The empty string is a correct bracket sequence by definition.A substring s[l... r] (1 ≤ l ≤ r ≤ |s|) of string s = s1s2... s|s| (where |s| is the length of string s) is the string slsl + 1... sr. The empty string is a substring of any string by definition.You are given a bracket sequence, not necessarily correct. Find its substring which is a correct bracket sequence and contains as many opening square brackets «[» as possible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"727"A monopole magnet is a magnet that only has one pole, either north or south. They don't actually exist since real magnets have two poles, but this is a programming contest problem, so we don't care.There is an $$$n\times m$$$ grid. Initially, you may place some north magnets and some south magnets into the cells. You are allowed to place as many magnets as you like, even multiple in the same cell.An operation is performed as follows. Choose a north magnet and a south magnet to activate. If they are in the same row or the same column and they occupy different cells, then the north magnet moves one unit closer to the south magnet. Otherwise, if they occupy the same cell or do not share a row or column, then nothing changes. Note that the south magnets are immovable.Each cell of the grid is colored black or white. Let's consider ways to place magnets in the cells so that the following conditions are met.  There is at least one south magnet in every row and every column.  If a cell is colored black, then it is possible for a north magnet to occupy this cell after some sequence of operations from the initial placement.  If a cell is colored white, then it is impossible for a north magnet to occupy this cell after some sequence of operations from the initial placement. Determine if it is possible to place magnets such that these conditions are met. If it is possible, find the minimum number of north magnets required (there are no requirements on the number of south magnets).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"728"At many competitions that have a word «cup» in its official name the winner is presented with an actual cup. This time the organizers of one unusual programming competition have decided to please the winner even more and to add a nameplate to the cup with the handle of the winner.The nameplate is to be rectangular and the text on it will be printed as a table of several rows and columns. Having some measurements done, the organizers have found out that the number $$$a$$$ of rows cannot be greater than $$$5$$$ while the number $$$b$$$ of columns cannot exceed $$$20$$$. Every cell of the table will contain either an asterisk («*») or a letter of user's handle.Furthermore, the organizers want the rows of the table to be uniform, which means that the number of asterisks used in different rows should differ by at most one (i.e. you can't have two asterisks in the first row and none in the second). The main goal, however, is to obtain the winner's handle precisely when reading the table from top to bottom and from left to right in every row (skipping asterisks).The organizers want for the nameplate to have as few rows as possible and among all valid tables with the minimum number of rows they want to choose the one that has the minimum number of columns.The winner is not yet determined so your task is to write a program that, given a certain handle, generates the necessary table.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"729"Once upon a time DravDe, an outstanding person famous for his professional achievements (as you must remember, he works in a warehouse storing Ogudar-Olok, a magical but non-alcoholic drink) came home after a hard day. That day he had to drink 9875 boxes of the drink and, having come home, he went to bed at once.DravDe dreamt about managing a successful farm. He dreamt that every day one animal came to him and asked him to let it settle there. However, DravDe, being unimaginably kind, could send the animal away and it went, rejected. There were exactly n days in DravDe’s dream and the animal that came on the i-th day, ate exactly ci tons of food daily starting from day i. But if one day the animal could not get the food it needed, it got really sad. At the very beginning of the dream there were exactly X tons of food on the farm.DravDe woke up terrified...When he retold the dream to you, he couldn’t remember how many animals were on the farm by the end of the n-th day any more, but he did remember that nobody got sad (as it was a happy farm) and that there was the maximum possible amount of the animals. That’s the number he wants you to find out. It should be noticed that the animals arrived in the morning and DravDe only started to feed them in the afternoon, so that if an animal willing to join them is rejected, it can’t eat any farm food. But if the animal does join the farm, it eats daily from that day to the n-th.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"730"You are given $$$n$$$ elements numbered from $$$1$$$ to $$$n$$$, the element $$$i$$$ has value $$$a_i$$$ and color $$$c_i$$$, initially, $$$c_i = 0$$$ for all $$$i$$$.The following operation can be applied:  Select three elements $$$i$$$, $$$j$$$ and $$$k$$$ ($$$1 \leq i < j < k \leq n$$$), such that $$$c_i$$$, $$$c_j$$$ and $$$c_k$$$ are all equal to $$$0$$$ and $$$a_i = a_k$$$, then set $$$c_j = 1$$$. Find the maximum value of $$$\sum\limits_{i=1}^n{c_i}$$$ that can be obtained after applying the given operation any number of times.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"731"There are $$$n$$$ students and $$$m$$$ clubs in a college. The clubs are numbered from $$$1$$$ to $$$m$$$. Each student has a potential $$$p_i$$$ and is a member of the club with index $$$c_i$$$. Initially, each student is a member of exactly one club. A technical fest starts in the college, and it will run for the next $$$d$$$ days. There is a coding competition every day in the technical fest. Every day, in the morning, exactly one student of the college leaves their club. Once a student leaves their club, they will never join any club again. Every day, in the afternoon, the director of the college will select one student from each club (in case some club has no members, nobody is selected from that club) to form a team for this day's coding competition. The strength of a team is the mex of potentials of the students in the team. The director wants to know the maximum possible strength of the team for each of the coming $$$d$$$ days. Thus, every day the director chooses such team, that the team strength is maximized.The mex of the multiset $$$S$$$ is the smallest non-negative integer that is not present in $$$S$$$. For example, the mex of the $$$\{0, 1, 1, 2, 4, 5, 9\}$$$ is $$$3$$$, the mex of $$$\{1, 2, 3\}$$$ is $$$0$$$ and the mex of $$$\varnothing$$$ (empty set) is $$$0$$$.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"732"There is a grid, consisting of $$$n$$$ rows and $$$m$$$ columns. The rows are numbered from $$$1$$$ to $$$n$$$ from bottom to top. The columns are numbered from $$$1$$$ to $$$m$$$ from left to right. The $$$i$$$-th column has the bottom $$$a_i$$$ cells blocked (the cells in rows $$$1, 2, \dots, a_i$$$), the remaining $$$n - a_i$$$ cells are unblocked.A robot is travelling across this grid. You can send it commands — move up, right, down or left. If a robot attempts to move into a blocked cell or outside the grid, it explodes.However, the robot is broken — it executes each received command $$$k$$$ times. So if you tell it to move up, for example, it will move up $$$k$$$ times ($$$k$$$ cells). You can't send it commands while the robot executes the current one.You are asked $$$q$$$ queries about the robot. Each query has a start cell, a finish cell and a value $$$k$$$. Can you send the robot an arbitrary number of commands (possibly, zero) so that it reaches the finish cell from the start cell, given that it executes each command $$$k$$$ times?The robot must stop in the finish cell. If it visits the finish cell while still executing commands, it doesn't count.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"733"While walking down the street Vanya saw a label ""Hide&Seek"". Because he is a programmer, he used & as a bitwise AND for these two words represented as a integers in base 64 and got new word. Now Vanya thinks of some string s and wants to know the number of pairs of words of length |s| (length of s), such that their bitwise AND is equal to s. As this number can be large, output it modulo 109 + 7.To represent the string as a number in numeral system with base 64 Vanya uses the following rules:  digits from '0' to '9' correspond to integers from 0 to 9;  letters from 'A' to 'Z' correspond to integers from 10 to 35;  letters from 'a' to 'z' correspond to integers from 36 to 61;  letter '-' correspond to integer 62;  letter '_' correspond to integer 63. ",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"734"Sereja has two sequences a and b and number p. Sequence a consists of n integers a1, a2, ..., an. Similarly, sequence b consists of m integers b1, b2, ..., bm. As usual, Sereja studies the sequences he has. Today he wants to find the number of positions q (q + (m - 1)·p ≤ n; q ≥ 1), such that sequence b can be obtained from sequence aq, aq + p, aq + 2p, ..., aq + (m - 1)p by rearranging elements.Sereja needs to rush to the gym, so he asked to find all the described positions of q.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"735"Consider the following problem: given an array $$$a$$$ containing $$$n$$$ integers (indexed from $$$0$$$ to $$$n-1$$$), find $$$\max\limits_{0 \leq l \leq r \leq n-1} \sum\limits_{l \leq i \leq r} (r-l+1) \cdot a_i$$$. In this problem, $$$1 \leq n \leq 2\,000$$$ and $$$|a_i| \leq 10^6$$$.In an attempt to solve the problem described, Alice quickly came up with a blazing-fast greedy algorithm and coded it. Her implementation in pseudocode is as follows:function find_answer(n, a)    # Assumes n is an integer between 1 and 2000, inclusive    # Assumes a is a list containing n integers: a[0], a[1], ..., a[n-1]    res = 0    cur = 0    k = -1    for i = 0 to i = n-1        cur = cur + a[i]        if cur < 0            cur = 0            k = i        res = max(res, (i-k)*cur)    return resAlso, as you can see, Alice's idea is not entirely correct. For example, suppose $$$n = 4$$$ and $$$a = [6, -8, 7, -42]$$$. Then, find_answer(n, a) would return $$$7$$$, but the correct answer is $$$3 \cdot (6-8+7) = 15$$$.You told Alice that her solution is incorrect, but she did not believe what you said.Given an integer $$$k$$$, you are to find any sequence $$$a$$$ of $$$n$$$ integers such that the correct answer and the answer produced by Alice's algorithm differ by exactly $$$k$$$. Note that although the choice of $$$n$$$ and the content of the sequence is yours, you must still follow the constraints earlier given: that $$$1 \leq n \leq 2\,000$$$ and that the absolute value of each element does not exceed $$$10^6$$$. If there is no such sequence, determine so.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"736"There is a string $$$s$$$ of length $$$3$$$, consisting of uppercase and lowercase English letters. Check if it is equal to ""YES"" (without quotes), where each letter can be in any case. For example, ""yES"", ""Yes"", ""yes"" are all allowable.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"737"You are given a string $$$s$$$. You need to find two non-empty strings $$$a$$$ and $$$b$$$ such that the following conditions are satisfied:  Strings $$$a$$$ and $$$b$$$ are both subsequences of $$$s$$$.  For each index $$$i$$$, character $$$s_i$$$ of string $$$s$$$ must belong to exactly one of strings $$$a$$$ or $$$b$$$.  String $$$a$$$ is lexicographically minimum possible; string $$$b$$$ may be any possible string. Given string $$$s$$$, print any valid $$$a$$$ and $$$b$$$.Reminder:A string $$$a$$$ ($$$b$$$) is a subsequence of a string $$$s$$$ if $$$a$$$ ($$$b$$$) can be obtained from $$$s$$$ by deletion of several (possibly, zero) elements. For example, ""dores"", ""cf"", and ""for"" are subsequences of ""codeforces"", while ""decor"" and ""fork"" are not.A string $$$x$$$ is lexicographically smaller than a string $$$y$$$ if and only if one of the following holds:  $$$x$$$ is a prefix of $$$y$$$, but $$$x \ne y$$$;  in the first position where $$$x$$$ and $$$y$$$ differ, the string $$$x$$$ has a letter that appears earlier in the alphabet than the corresponding letter in $$$y$$$. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"738"Let $$$s$$$ be a string of lowercase Latin letters. Its price is the sum of the indices of letters (an integer between 1 and 26) that are included in it. For example, the price of the string abca is $$$1+2+3+1=7$$$.The string $$$w$$$ and the integer $$$p$$$ are given. Remove the minimal number of letters from $$$w$$$ so that its price becomes less than or equal to $$$p$$$ and print the resulting string. Note that the resulting string may be empty. You can delete arbitrary letters, they do not have to go in a row. If the price of a given string $$$w$$$ is less than or equal to $$$p$$$, then nothing needs to be deleted and $$$w$$$ must be output.Note that when you delete a letter from $$$w$$$, the order of the remaining letters is preserved. For example, if you delete the letter e from the string test, you get tst.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"739"In the game Lizard Era: Beginning the protagonist will travel with three companions: Lynn, Meliana and Worrigan. Overall the game has n mandatory quests. To perform each of them, you need to take exactly two companions.The attitude of each of the companions to the hero is an integer. Initially, the attitude of each of them to the hero of neutral and equal to 0. As the hero completes quests, he makes actions that change the attitude of the companions, whom he took to perform this task, in positive or negative direction.Tell us what companions the hero needs to choose to make their attitude equal after completing all the quests. If this can be done in several ways, choose the one in which the value of resulting attitude is greatest possible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"740"The country has n cities and n - 1 bidirectional roads, it is possible to get from every city to any other one if you move only along the roads. The cities are numbered with integers from 1 to n inclusive.All the roads are initially bad, but the government wants to improve the state of some roads. We will assume that the citizens are happy about road improvement if the path from the capital located in city x to any other city contains at most one bad road.Your task is — for every possible x determine the number of ways of improving the quality of some roads in order to meet the citizens' condition. As those values can be rather large, you need to print each value modulo 1 000 000 007 (109 + 7).",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"741"You and your friend are playing the game Mortal Kombat XI. You are trying to pass a challenge tower. There are $$$n$$$ bosses in this tower, numbered from $$$1$$$ to $$$n$$$. The type of the $$$i$$$-th boss is $$$a_i$$$. If the $$$i$$$-th boss is easy then its type is $$$a_i = 0$$$, otherwise this boss is hard and its type is $$$a_i = 1$$$.During one session, either you or your friend can kill one or two bosses (neither you nor your friend can skip the session, so the minimum number of bosses killed during one session is at least one). After your friend session, your session begins, then again your friend session begins, your session begins, and so on. The first session is your friend's session.Your friend needs to get good because he can't actually kill hard bosses. To kill them, he uses skip points. One skip point can be used to kill one hard boss.Your task is to find the minimum number of skip points your friend needs to use so you and your friend kill all $$$n$$$ bosses in the given order.For example: suppose $$$n = 8$$$, $$$a = [1, 0, 1, 1, 0, 1, 1, 1]$$$. Then the best course of action is the following:  your friend kills two first bosses, using one skip point for the first boss;  you kill the third and the fourth bosses;  your friend kills the fifth boss;  you kill the sixth and the seventh bosses;  your friend kills the last boss, using one skip point, so the tower is completed using two skip points. You have to answer $$$t$$$ independent test cases.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"742"You are given an array $$$c = [c_1, c_2, \dots, c_m]$$$. An array $$$a = [a_1, a_2, \dots, a_n]$$$ is constructed in such a way that it consists of integers $$$1, 2, \dots, m$$$, and for each $$$i \in [1,m]$$$, there are exactly $$$c_i$$$ occurrences of integer $$$i$$$ in $$$a$$$. So, the number of elements in $$$a$$$ is exactly $$$\sum\limits_{i=1}^{m} c_i$$$.Let's define for such array $$$a$$$ the value $$$f(a)$$$ as $$$$$$f(a) = \sum_{\substack{1 \le i < j \le n\\ a_i = a_j}}{j - i}.$$$$$$In other words, $$$f(a)$$$ is the total sum of distances between all pairs of equal elements.Your task is to calculate the maximum possible value of $$$f(a)$$$ and the number of arrays yielding the maximum possible value of $$$f(a)$$$. Two arrays are considered different, if elements at some position differ.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"743"This is an interactive problem.Ayush devised yet another scheme to set the password of his lock. The lock has $$$n$$$ slots where each slot can hold any non-negative integer. The password $$$P$$$ is a sequence of $$$n$$$ integers, $$$i$$$-th element of which goes into the $$$i$$$-th slot of the lock.To set the password, Ayush comes up with an array $$$A$$$ of $$$n$$$ integers each in the range $$$[0, 2^{63}-1]$$$. He then sets the $$$i$$$-th element of $$$P$$$ as the bitwise OR of all integers in the array except $$$A_i$$$.You need to guess the password. To make a query, you can choose a non-empty subset of indices of the array and ask the bitwise OR all elements of the array with index in this subset. You can ask no more than 13 queries.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"744"Some number of people (this number is even) have stood in a circle. The people stand in the circle evenly. They are numbered clockwise starting from a person with the number $$$1$$$. Each person is looking through the circle's center at the opposite person.    A sample of a circle of $$$6$$$ persons. The orange arrows indicate who is looking at whom. You don't know the exact number of people standing in the circle (but this number is even, no doubt). It is known that the person with the number $$$a$$$ is looking at the person with the number $$$b$$$ (and vice versa, of course). What is the number associated with a person being looked at by the person with the number $$$c$$$? If, for the specified $$$a$$$, $$$b$$$, and $$$c$$$, no such circle exists, output -1.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"745"A very brave explorer Petya once decided to explore Paris catacombs. Since Petya is not really experienced, his exploration is just walking through the catacombs.Catacombs consist of several rooms and bidirectional passages between some pairs of them. Some passages can connect a room to itself and since the passages are built on different depths they do not intersect each other. Every minute Petya arbitrary chooses a passage from the room he is currently in and then reaches the room on the other end of the passage in exactly one minute. When he enters a room at minute i, he makes a note in his logbook with number ti:   If Petya has visited this room before, he writes down the minute he was in this room last time;  Otherwise, Petya writes down an arbitrary non-negative integer strictly less than current minute i. Initially, Petya was in one of the rooms at minute 0, he didn't write down number t0.At some point during his wandering Petya got tired, threw out his logbook and went home. Vasya found his logbook and now he is curious: what is the minimum possible number of rooms in Paris catacombs according to Petya's logbook?",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"746"You need to find a binary tree of size n that satisfies a given set of c constraints. Suppose that the nodes of the unknown binary tree are labeled using a pre-order traversal starting with 1. For the i-th constraint you are given two labels, ai and bi and a direction, left or right. In case of left direction, bi is an element of the subtree rooted at ai's left child. Similarly in the case of right direction bi is an element of the subtree rooted at ai's right child.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"747"Given a permutation $$$a_1, a_2, \dots, a_n$$$ of integers from $$$1$$$ to $$$n$$$, and a threshold $$$k$$$ with $$$0 \leq k \leq n$$$, you compute a sequence $$$b_1, b_2, \dots, b_n$$$ as follows. For every $$$1 \leq i \leq n$$$ in increasing order, let $$$x = a_i$$$.   If $$$x \leq k$$$, set $$$b_{x}$$$ to the last element $$$a_j$$$ ($$$1 \leq j < i$$$) that $$$a_j > k$$$. If no such element $$$a_j$$$ exists, set $$$b_{x} = n+1$$$.  If $$$x > k$$$, set $$$b_{x}$$$ to the last element $$$a_j$$$ ($$$1 \leq j < i$$$) that $$$a_j \leq k$$$. If no such element $$$a_j$$$ exists, set $$$b_{x} = 0$$$. Unfortunately, after the sequence $$$b_1, b_2, \dots, b_n$$$ has been completely computed, the permutation $$$a_1, a_2, \dots, a_n$$$ and the threshold $$$k$$$ are discarded. Now you only have the sequence $$$b_1, b_2, \dots, b_n$$$. Your task is to find any possible permutation $$$a_1, a_2, \dots, a_n$$$ and threshold $$$k$$$ that produce the sequence $$$b_1, b_2, \dots, b_n$$$. It is guaranteed that there exists at least one pair of permutation $$$a_1, a_2, \dots, a_n$$$ and threshold $$$k$$$ that produce the sequence $$$b_1, b_2, \dots, b_n$$$.A permutation of integers from $$$1$$$ to $$$n$$$ is a sequence of length $$$n$$$ which contains all integers from $$$1$$$ to $$$n$$$ exactly once. ","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"748"You are a coach at your local university. There are $$$n$$$ students under your supervision, the programming skill of the $$$i$$$-th student is $$$a_i$$$.You have to create a team for a new programming competition. As you know, the more students some team has the more probable its victory is! So you have to create a team with the maximum number of students. But you also know that a team should be balanced. It means that the programming skill of each pair of students in a created team should differ by no more than $$$5$$$.Your task is to report the maximum possible number of students in a balanced team.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"749"PMP is getting a warrior. He is practicing a lot, but the results are not acceptable yet. This time instead of programming contests, he decided to compete in a car racing to increase the spirit of victory. He decides to choose a competition that also exhibits algorithmic features.AlgoRace is a special league of car racing where different teams compete in a country of n cities. Cities are numbered 1 through n. Every two distinct cities in the country are connected with one bidirectional road. Each competing team should introduce one driver and a set of cars.The competition is held in r rounds. In i-th round, drivers will start at city si and finish at city ti. Drivers are allowed to change their cars at most ki times. Changing cars can take place in any city in no time. One car can be used multiple times in one round, but total number of changes should not exceed ki. Drivers can freely choose their path to destination.PMP has prepared m type of purpose-built cars. Beside for PMP’s driving skills, depending on properties of the car and the road, a car traverses each road in each direction in different times. PMP Warriors wants to devise best strategies of choosing car and roads in each round to maximize the chance of winning the cup. For each round they want to find the minimum time required to finish it.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"750"Hooray! Berl II, the king of Berland is making a knight tournament. The king has already sent the message to all knights in the kingdom and they in turn agreed to participate in this grand event.As for you, you're just a simple peasant. There's no surprise that you slept in this morning and were late for the tournament (it was a weekend, after all). Now you are really curious about the results of the tournament. This time the tournament in Berland went as follows:  There are n knights participating in the tournament. Each knight was assigned his unique number — an integer from 1 to n.  The tournament consisted of m fights, in the i-th fight the knights that were still in the game with numbers at least li and at most ri have fought for the right to continue taking part in the tournament.  After the i-th fight among all participants of the fight only one knight won — the knight number xi, he continued participating in the tournament. Other knights left the tournament.  The winner of the last (the m-th) fight (the knight number xm) became the winner of the tournament. You fished out all the information about the fights from your friends. Now for each knight you want to know the name of the knight he was conquered by. We think that the knight number b was conquered by the knight number a, if there was a fight with both of these knights present and the winner was the knight number a.Write the code that calculates for each knight, the name of the knight that beat him.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"751"Vasya has got an array consisting of $$$n$$$ integers, and two integers $$$k$$$ and $$$len$$$ in addition. All numbers in the array are either between $$$1$$$ and $$$k$$$ (inclusive), or equal to $$$-1$$$. The array is good if there is no segment of $$$len$$$ consecutive equal numbers.Vasya will replace each $$$-1$$$ with some number from $$$1$$$ to $$$k$$$ (inclusive) in such a way that the resulting array is good. Tell him the number of ways to do this replacement. Since the answer may be large, print it modulo $$$998244353$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"752"Petya loves lucky numbers. Everybody knows that positive integers are lucky if their decimal representation doesn't contain digits other than 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.Lucky number is super lucky if it's decimal representation contains equal amount of digits 4 and 7. For example, numbers 47, 7744, 474477 are super lucky and 4, 744, 467 are not.One day Petya came across a positive integer n. Help him to find the least super lucky number which is not less than n.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"753"The heat during the last few days has been really intense. Scientists from all over the Berland study how the temperatures and weather change, and they claim that this summer is abnormally hot. But any scientific claim sounds a lot more reasonable if there are some numbers involved, so they have decided to actually calculate some value which would represent how high the temperatures are.Mathematicians of Berland State University came up with a special heat intensity value. This value is calculated as follows:Suppose we want to analyze the segment of $$$n$$$ consecutive days. We have measured the temperatures during these $$$n$$$ days; the temperature during $$$i$$$-th day equals $$$a_i$$$.We denote the average temperature of a segment of some consecutive days as the arithmetic mean of the temperature measures during this segment of days. So, if we want to analyze the average temperature from day $$$x$$$ to day $$$y$$$, we calculate it as $$$\frac{\sum \limits_{i = x}^{y} a_i}{y - x + 1}$$$ (note that division is performed without any rounding). The heat intensity value is the maximum of average temperatures over all segments of not less than $$$k$$$ consecutive days. For example, if analyzing the measures $$$[3, 4, 1, 2]$$$ and $$$k = 3$$$, we are interested in segments $$$[3, 4, 1]$$$, $$$[4, 1, 2]$$$ and $$$[3, 4, 1, 2]$$$ (we want to find the maximum value of average temperature over these segments).You have been hired by Berland State University to write a program that would compute the heat intensity value of a given period of days. Are you up to this task?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"754"Lunar New Year is approaching, and Bob is struggling with his homework – a number division problem.There are $$$n$$$ positive integers $$$a_1, a_2, \ldots, a_n$$$ on Bob's homework paper, where $$$n$$$ is always an even number. Bob is asked to divide those numbers into groups, where each group must contain at least $$$2$$$ numbers. Suppose the numbers are divided into $$$m$$$ groups, and the sum of the numbers in the $$$j$$$-th group is $$$s_j$$$. Bob's aim is to minimize the sum of the square of $$$s_j$$$, that is $$$$$$\sum_{j = 1}^{m} s_j^2.$$$$$$Bob is puzzled by this hard problem. Could you please help him solve it?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"755"You are given a n × m field consisting only of periods ('.') and asterisks ('*'). Your task is to count all right triangles with two sides parallel to the square sides, whose vertices are in the centers of '*'-cells. A right triangle is a triangle in which one angle is a right angle (that is, a 90 degree angle).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"756"The Berland Armed Forces System consists of n ranks that are numbered using natural numbers from 1 to n, where 1 is the lowest rank and n is the highest rank.One needs exactly di years to rise from rank i to rank i + 1. Reaching a certain rank i having not reached all the previous i - 1 ranks is impossible.Vasya has just reached a new rank of a, but he dreams of holding the rank of b. Find for how many more years Vasya should serve in the army until he can finally realize his dream.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"757"You are given four integers $$$a$$$, $$$b$$$, $$$x$$$ and $$$y$$$. Initially, $$$a \ge x$$$ and $$$b \ge y$$$. You can do the following operation no more than $$$n$$$ times:  Choose either $$$a$$$ or $$$b$$$ and decrease it by one. However, as a result of this operation, value of $$$a$$$ cannot become less than $$$x$$$, and value of $$$b$$$ cannot become less than $$$y$$$. Your task is to find the minimum possible product of $$$a$$$ and $$$b$$$ ($$$a \cdot b$$$) you can achieve by applying the given operation no more than $$$n$$$ times.You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"758"Lee couldn't sleep lately, because he had nightmares. In one of his nightmares (which was about an unbalanced global round), he decided to fight back and propose a problem below (which you should solve) to balance the round, hopefully setting him free from the nightmares.A non-empty array $$$b_1, b_2, \ldots, b_m$$$ is called good, if there exist $$$m$$$ integer sequences which satisfy the following properties:  The $$$i$$$-th sequence consists of $$$b_i$$$ consecutive integers (for example if $$$b_i = 3$$$ then the $$$i$$$-th sequence can be $$$(-1, 0, 1)$$$ or $$$(-5, -4, -3)$$$ but not $$$(0, -1, 1)$$$ or $$$(1, 2, 3, 4)$$$).  Assuming the sum of integers in the $$$i$$$-th sequence is $$$sum_i$$$, we want $$$sum_1 + sum_2 + \ldots + sum_m$$$ to be equal to $$$0$$$. You are given an array $$$a_1, a_2, \ldots, a_n$$$. It has $$$2^n - 1$$$ nonempty subsequences. Find how many of them are good.As this number can be very large, output it modulo $$$10^9 + 7$$$.An array $$$c$$$ is a subsequence of an array $$$d$$$ if $$$c$$$ can be obtained from $$$d$$$ by deletion of several (possibly, zero or all) elements.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"759"People in the Tomskaya region like magic formulas very much. You can see some of them below.Imagine you are given a sequence of positive integer numbers p1, p2, ..., pn. Lets write down some magic formulas:Here, ""mod"" means the operation of taking the residue after dividing.The expression  means applying the bitwise xor (excluding ""OR"") operation to integers x and y. The given operation exists in all modern programming languages. For example, in languages C++ and Java it is represented by ""^"", in Pascal — by ""xor"".People in the Tomskaya region like magic formulas very much, but they don't like to calculate them! Therefore you are given the sequence p, calculate the value of Q.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"760"Limak is a little polar bear. He plays by building towers from blocks. Every block is a cube with positive integer length of side. Limak has infinitely many blocks of each side length.A block with side a has volume a3. A tower consisting of blocks with sides a1, a2, ..., ak has the total volume a13 + a23 + ... + ak3.Limak is going to build a tower. First, he asks you to tell him a positive integer X — the required total volume of the tower. Then, Limak adds new blocks greedily, one by one. Each time he adds the biggest block such that the total volume doesn't exceed X.Limak asks you to choose X not greater than m. Also, he wants to maximize the number of blocks in the tower at the end (however, he still behaves greedily). Secondarily, he wants to maximize X.Can you help Limak? Find the maximum number of blocks his tower can have and the maximum X ≤ m that results this number of blocks.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"761"A wise man told Kerem ""Different is good"" once, so Kerem wants all things in his life to be different. Kerem recently got a string s consisting of lowercase English letters. Since Kerem likes it when things are different, he wants all substrings of his string s to be distinct. Substring is a string formed by some number of consecutive characters of the string. For example, string ""aba"" has substrings """" (empty substring), ""a"", ""b"", ""a"", ""ab"", ""ba"", ""aba"".If string s has at least two equal substrings then Kerem will change characters at some positions to some other lowercase English letters. Changing characters is a very tiring job, so Kerem want to perform as few changes as possible.Your task is to find the minimum number of changes needed to make all the substrings of the given string distinct, or determine that it is impossible.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"762"Tokitsukaze has a permutation $$$p$$$. She performed the following operation to $$$p$$$ exactly $$$k$$$ times: in one operation, for each $$$i$$$ from $$$1$$$ to $$$n - 1$$$ in order, if $$$p_i$$$ > $$$p_{i+1}$$$, swap $$$p_i$$$, $$$p_{i+1}$$$. After exactly $$$k$$$ times of operations, Tokitsukaze got a new sequence $$$a$$$, obviously the sequence $$$a$$$ is also a permutation.After that, Tokitsukaze wrote down the value sequence $$$v$$$ of $$$a$$$ on paper. Denote the value sequence $$$v$$$ of the permutation $$$a$$$ of length $$$n$$$ as $$$v_i=\sum_{j=1}^{i-1}[a_i < a_j]$$$, where the value of $$$[a_i < a_j]$$$ define as if $$$a_i < a_j$$$, the value is $$$1$$$, otherwise is $$$0$$$ (in other words, $$$v_i$$$ is equal to the number of elements greater than $$$a_i$$$ that are to the left of position $$$i$$$). Then Tokitsukaze went out to work.There are three naughty cats in Tokitsukaze's house. When she came home, she found the paper with the value sequence $$$v$$$ to be bitten out by the cats, leaving several holes, so that the value of some positions could not be seen clearly. She forgot what the original permutation $$$p$$$ was. She wants to know how many different permutations $$$p$$$ there are, so that the value sequence $$$v$$$ of the new permutation $$$a$$$ after exactly $$$k$$$ operations is the same as the $$$v$$$ written on the paper (not taking into account the unclear positions).Since the answer may be too large, print it modulo $$$998\,244\,353$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"763"You have a playlist consisting of $$$n$$$ songs. The $$$i$$$-th song is characterized by two numbers $$$t_i$$$ and $$$b_i$$$ — its length and beauty respectively. The pleasure of listening to set of songs is equal to the total length of the songs in the set multiplied by the minimum beauty among them. For example, the pleasure of listening to a set of $$$3$$$ songs having lengths $$$[5, 7, 4]$$$ and beauty values $$$[11, 14, 6]$$$ is equal to $$$(5 + 7 + 4) \cdot 6 = 96$$$.You need to choose at most $$$k$$$ songs from your playlist, so the pleasure of listening to the set of these songs them is maximum possible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"764"Little time is left before Berland annual football championship. Therefore the coach of team ""Losewille Rangers"" decided to resume the practice, that were indefinitely interrupted for uncertain reasons. Overall there are n players in ""Losewille Rangers"". Each player on the team has a number — a unique integer from 1 to n. To prepare for the championship, the coach Mr. Floppe decided to spend some number of practices.Mr. Floppe spent some long nights of his holiday planning how to conduct the practices. He came to a very complex practice system. Each practice consists of one game, all n players of the team take part in the game. The players are sorted into two teams in some way. In this case, the teams may have different numbers of players, but each team must have at least one player.The coach wants to be sure that after the series of the practice sessions each pair of players had at least one practice, when they played in different teams. As the players' energy is limited, the coach wants to achieve the goal in the least number of practices.Help him to schedule the practices.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"765"In the rush of modern life, people often forget how beautiful the world is. The time to enjoy those around them is so little that some even stand in queues to several rooms at the same time in the clinic, running from one queue to another.(Cultural note: standing in huge and disorganized queues for hours is a native tradition in Russia, dating back to the Soviet period. Queues can resemble crowds rather than lines. Not to get lost in such a queue, a person should follow a strict survival technique: you approach the queue and ask who the last person is, somebody answers and you join the crowd. Now you're the last person in the queue till somebody else shows up. You keep an eye on the one who was last before you as he is your only chance to get to your destination) I'm sure many people have had the problem when a stranger asks who the last person in the queue is and even dares to hint that he will be the last in the queue and then bolts away to some unknown destination. These are the representatives of the modern world, in which the ratio of lack of time is so great that they do not even watch foreign top-rated TV series. Such people often create problems in queues, because the newcomer does not see the last person in the queue and takes a place after the ""virtual"" link in this chain, wondering where this legendary figure has left.The Smart Beaver has been ill and he's made an appointment with a therapist. The doctor told the Beaver the sad news in a nutshell: it is necessary to do an electrocardiogram. The next day the Smart Beaver got up early, put on the famous TV series on download (three hours till the download's complete), clenched his teeth and bravely went to join a queue to the electrocardiogram room, which is notorious for the biggest queues at the clinic.Having stood for about three hours in the queue, the Smart Beaver realized that many beavers had not seen who was supposed to stand in the queue before them and there was a huge mess. He came up to each beaver in the ECG room queue and asked who should be in front of him in the queue. If the beaver did not know his correct position in the queue, then it might be his turn to go get an ECG, or maybe he should wait for a long, long time...As you've guessed, the Smart Beaver was in a hurry home, so he gave you all the necessary information for you to help him to determine what his number in the queue can be.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"766"We all know the impressive story of Robin Hood. Robin Hood uses his archery skills and his wits to steal the money from rich, and return it to the poor.There are n citizens in Kekoland, each person has ci coins. Each day, Robin Hood will take exactly 1 coin from the richest person in the city and he will give it to the poorest person (poorest person right after taking richest's 1 coin). In case the choice is not unique, he will select one among them at random. Sadly, Robin Hood is old and want to retire in k days. He decided to spend these last days with helping poor people. After taking his money are taken by Robin Hood richest person may become poorest person as well, and it might even happen that Robin Hood will give his money back. For example if all people have same number of coins, then next day they will have same number of coins too. Your task is to find the difference between richest and poorest persons wealth after k days. Note that the choosing at random among richest and poorest doesn't affect the answer.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"767"Many years have passed, and n friends met at a party again. Technologies have leaped forward since the last meeting, cameras with timer appeared and now it is not obligatory for one of the friends to stand with a camera, and, thus, being absent on the photo.Simply speaking, the process of photographing can be described as follows. Each friend occupies a rectangle of pixels on the photo: the i-th of them in a standing state occupies a wi pixels wide and a hi pixels high rectangle. But also, each person can lie down for the photo, and then he will occupy a hi pixels wide and a wi pixels high rectangle.The total photo will have size W × H, where W is the total width of all the people rectangles, and H is the maximum of the heights. The friends want to determine what minimum area the group photo can they obtain if no more than n / 2 of them can lie on the ground (it would be strange if more than n / 2 gentlemen lie on the ground together, isn't it?..)Help them to achieve this goal.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"768"A bracket sequence is a string containing only characters ""("" and "")"". A regular bracket sequence (or, shortly, an RBS) is a bracket sequence that can be transformed into a correct arithmetic expression by inserting characters ""1"" and ""+"" between the original characters of the sequence. For example:  bracket sequences ""()()"" and ""(())"" are regular (the resulting expressions are: ""(1)+(1)"" and ""((1+1)+1)"");  bracket sequences "")("", ""("" and "")"" are not. Let's denote the concatenation of two strings $$$x$$$ and $$$y$$$ as $$$x+y$$$. For example, ""()()"" $$$+$$$ "")("" $$$=$$$ ""()())("".You are given $$$n$$$ bracket sequences $$$s_1, s_2, \dots, s_n$$$. You can rearrange them in any order (you can rearrange only the strings themselves, but not the characters in them).Your task is to rearrange the strings in such a way that the string $$$s_1 + s_2 + \dots + s_n$$$ has as many non-empty prefixes that are RBS as possible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"769"Suppose you are performing the following algorithm. There is an array $$$v_1, v_2, \dots, v_n$$$ filled with zeroes at start. The following operation is applied to the array several times — at $$$i$$$-th step ($$$0$$$-indexed) you can:   either choose position $$$pos$$$ ($$$1 \le pos \le n$$$) and increase $$$v_{pos}$$$ by $$$k^i$$$;  or not choose any position and skip this step. You can choose how the algorithm would behave on each step and when to stop it. The question is: can you make array $$$v$$$ equal to the given array $$$a$$$ ($$$v_j = a_j$$$ for each $$$j$$$) after some step?","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"770"Your friend Jeff Zebos has been trying to run his new online company, but it's not going very well. He's not getting a lot of sales on his website which he decided to call Azamon. His big problem, you think, is that he's not ranking high enough on the search engines. If only he could rename his products to have better names than his competitors, then he'll be at the top of the search results and will be a millionaire.After doing some research, you find out that search engines only sort their results lexicographically. If your friend could rename his products to lexicographically smaller strings than his competitor's, then he'll be at the top of the rankings!To make your strategy less obvious to his competitors, you decide to swap no more than two letters of the product names.Please help Jeff to find improved names for his products that are lexicographically smaller than his competitor's!Given the string $$$s$$$ representing Jeff's product name and the string $$$c$$$ representing his competitor's product name, find a way to swap at most one pair of characters in $$$s$$$ (that is, find two distinct indices $$$i$$$ and $$$j$$$ and swap $$$s_i$$$ and $$$s_j$$$) such that the resulting new name becomes strictly lexicographically smaller than $$$c$$$, or determine that it is impossible.Note: String $$$a$$$ is strictly lexicographically smaller than string $$$b$$$ if and only if one of the following holds:  $$$a$$$ is a proper prefix of $$$b$$$, that is, $$$a$$$ is a prefix of $$$b$$$ such that $$$a \neq b$$$;  There exists an integer $$$1 \le i \le \min{(|a|, |b|)}$$$ such that $$$a_i < b_i$$$ and $$$a_j = b_j$$$ for $$$1 \le j < i$$$. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"771"In this problem you have to implement an algorithm to defragment your hard disk. The hard disk consists of a sequence of clusters, numbered by integers from 1 to n. The disk has m recorded files, the i-th file occupies clusters with numbers ai, 1, ai, 2, ..., ai, ni. These clusters are not necessarily located consecutively on the disk, but the order in which they are given corresponds to their sequence in the file (cluster ai, 1 contains the first fragment of the i-th file, cluster ai, 2 has the second fragment, etc.). Also the disc must have one or several clusters which are free from files.You are permitted to perform operations of copying the contents of cluster number i to cluster number j (i and j must be different). Moreover, if the cluster number j used to keep some information, it is lost forever. Clusters are not cleaned, but after the defragmentation is complete, some of them are simply declared unusable (although they may possibly still contain some fragments of files).Your task is to use a sequence of copy operations to ensure that each file occupies a contiguous area of memory. Each file should occupy a consecutive cluster section, the files must follow one after another from the beginning of the hard disk. After defragmentation all free (unused) clusters should be at the end of the hard disk. After defragmenting files can be placed in an arbitrary order. Clusters of each file should go consecutively from first to last. See explanatory examples in the notes.Print the sequence of operations leading to the disk defragmentation. Note that you do not have to minimize the number of operations, but it should not exceed 2n.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"772"You are given a string $$$s$$$, consisting only of characters '0' and '1'.You have to choose a contiguous substring of $$$s$$$ and remove all occurrences of the character, which is a strict minority in it, from the substring.That is, if the amount of '0's in the substring is strictly smaller than the amount of '1's, remove all occurrences of '0' from the substring. If the amount of '1's is strictly smaller than the amount of '0's, remove all occurrences of '1'. If the amounts are the same, do nothing.You have to apply the operation exactly once. What is the maximum amount of characters that can be removed?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"773"Riley is a very bad boy, but at the same time, he is a yo-yo master. So, he decided to use his yo-yo skills to annoy his friend Anton.Anton's room can be represented as a grid with $$$n$$$ rows and $$$m$$$ columns. Let $$$(i, j)$$$ denote the cell in row $$$i$$$ and column $$$j$$$. Anton is currently standing at position $$$(i, j)$$$ in his room. To annoy Anton, Riley decided to throw exactly two yo-yos in cells of the room (they can be in the same cell).Because Anton doesn't like yo-yos thrown on the floor, he has to pick up both of them and return back to the initial position. The distance travelled by Anton is the shortest path that goes through the positions of both yo-yos and returns back to $$$(i, j)$$$ by travelling only to adjacent by side cells. That is, if he is in cell $$$(x, y)$$$ then he can travel to the cells $$$(x + 1, y)$$$, $$$(x - 1, y)$$$, $$$(x, y + 1)$$$ and $$$(x, y - 1)$$$ in one step (if a cell with those coordinates exists).Riley is wondering where he should throw these two yo-yos so that the distance travelled by Anton is maximized. But because he is very busy, he asked you to tell him.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"774"Sereja loves all sorts of algorithms. He has recently come up with a new algorithm, which receives a string as an input. Let's represent the input string of the algorithm as q = q1q2... qk. The algorithm consists of two steps:  Find any continuous subsequence (substring) of three characters of string q, which doesn't equal to either string ""zyx"", ""xzy"", ""yxz"". If q doesn't contain any such subsequence, terminate the algorithm, otherwise go to step 2.  Rearrange the letters of the found subsequence randomly and go to step 1. Sereja thinks that the algorithm works correctly on string q if there is a non-zero probability that the algorithm will be terminated. But if the algorithm anyway will work for infinitely long on a string, then we consider the algorithm to work incorrectly on this string.Sereja wants to test his algorithm. For that, he has string s = s1s2... sn, consisting of n characters. The boy conducts a series of m tests. As the i-th test, he sends substring slisli + 1... sri (1 ≤ li ≤ ri ≤ n) to the algorithm input. Unfortunately, the implementation of his algorithm works too long, so Sereja asked you to help. For each test (li, ri) determine if the algorithm works correctly on this test or not.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"775"Pasha is participating in a contest on one well-known website. This time he wants to win the contest and will do anything to get to the first place!This contest consists of n problems, and Pasha solves ith problem in ai time units (his solutions are always correct). At any moment of time he can be thinking about a solution to only one of the problems (that is, he cannot be solving two problems at the same time). The time Pasha spends to send his solutions is negligible. Pasha can send any number of solutions at the same moment.Unfortunately, there are too many participants, and the website is not always working. Pasha received the information that the website will be working only during m time periods, jth period is represented by its starting moment lj and ending moment rj. Of course, Pasha can send his solution only when the website is working. In other words, Pasha can send his solution at some moment T iff there exists a period x such that lx ≤ T ≤ rx.Pasha wants to know his best possible result. We need to tell him the minimal moment of time by which he is able to have solutions to all problems submitted, if he acts optimally, or say that it's impossible no matter how Pasha solves the problems.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"776"You are given a rectangular parallelepiped with sides of positive integer lengths $$$A$$$, $$$B$$$ and $$$C$$$. Find the number of different groups of three integers ($$$a$$$, $$$b$$$, $$$c$$$) such that $$$1\leq a\leq b\leq c$$$ and parallelepiped $$$A\times B\times C$$$ can be paved with parallelepipeds $$$a\times b\times c$$$. Note, that all small parallelepipeds have to be rotated in the same direction.For example, parallelepiped $$$1\times 5\times 6$$$ can be divided into parallelepipeds $$$1\times 3\times 5$$$, but can not be divided into parallelepipeds $$$1\times 2\times 3$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"777"The Bad Luck Island is inhabited by three kinds of species: r rocks, s scissors and p papers. At some moments of time two random individuals meet (all pairs of individuals can meet equiprobably), and if they belong to different species, then one individual kills the other one: a rock kills scissors, scissors kill paper, and paper kills a rock. Your task is to determine for each species what is the probability that this species will be the only one to inhabit this island after a long enough period of time.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"778"Efim just received his grade for the last test. He studies in a special school and his grade can be equal to any positive decimal fraction. First he got disappointed, as he expected a way more pleasant result. Then, he developed a tricky plan. Each second, he can ask his teacher to round the grade at any place after the decimal point (also, he can ask to round to the nearest integer). There are t seconds left till the end of the break, so Efim has to act fast. Help him find what is the maximum grade he can get in no more than t seconds. Note, that he can choose to not use all t seconds. Moreover, he can even choose to not round the grade at all.In this problem, classic rounding rules are used: while rounding number to the n-th digit one has to take a look at the digit n + 1. If it is less than 5 than the n-th digit remain unchanged while all subsequent digits are replaced with 0. Otherwise, if the n + 1 digit is greater or equal to 5, the digit at the position n is increased by 1 (this might also change some other digits, if this one was equal to 9) and all subsequent digits are replaced with 0. At the end, all trailing zeroes are thrown away.For example, if the number 1.14 is rounded to the first decimal place, the result is 1.1, while if we round 1.5 to the nearest integer, the result is 2. Rounding number 1.299996121 in the fifth decimal place will result in number 1.3.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"779"You are given n segments on the Ox-axis. You can drive a nail in any integer point on the Ox-axis line nail so, that all segments containing this point, are considered nailed down. If the nail passes through endpoint of some segment, this segment is considered to be nailed too. What is the smallest number of nails needed to nail all the segments down?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"780"Memory is performing a walk on the two-dimensional plane, starting at the origin. He is given a string s with his directions for motion: An 'L' indicates he should move one unit left.  An 'R' indicates he should move one unit right.  A 'U' indicates he should move one unit up.  A 'D' indicates he should move one unit down.But now Memory wants to end at the origin. To do this, he has a special trident. This trident can replace any character in s with any of 'L', 'R', 'U', or 'D'. However, because he doesn't want to wear out the trident, he wants to make the minimum number of edits possible. Please tell Memory what is the minimum number of changes he needs to make to produce a string that, when walked, will end at the origin, or if there is no such string.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"781"Bertown has n junctions and m bidirectional roads. We know that one can get from any junction to any other one by the existing roads. As there were more and more cars in the city, traffic jams started to pose real problems. To deal with them the government decided to make the traffic one-directional on all the roads, thus easing down the traffic. Your task is to determine whether there is a way to make the traffic one-directional so that there still is the possibility to get from any junction to any other one. If the answer is positive, you should also find one of the possible ways to orient the roads.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"782"You are given an integer $$$n$$$ ($$$n \ge 0$$$) represented with $$$k$$$ digits in base (radix) $$$b$$$. So,$$$$$$n = a_1 \cdot b^{k-1} + a_2 \cdot b^{k-2} + \ldots a_{k-1} \cdot b + a_k.$$$$$$For example, if $$$b=17, k=3$$$ and $$$a=[11, 15, 7]$$$ then $$$n=11\cdot17^2+15\cdot17+7=3179+255+7=3441$$$.Determine whether $$$n$$$ is even or odd.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"783"A number of skyscrapers have been built in a line. The number of skyscrapers was chosen uniformly at random between 2 and 314! (314 factorial, a very large number). The height of each skyscraper was chosen randomly and independently, with height i having probability 2 - i for all positive integers i. The floors of a skyscraper with height i are numbered 0 through i - 1.To speed up transit times, a number of zip lines were installed between skyscrapers. Specifically, there is a zip line connecting the i-th floor of one skyscraper with the i-th floor of another skyscraper if and only if there are no skyscrapers between them that have an i-th floor.Alice and Bob decide to count the number of skyscrapers.Alice is thorough, and wants to know exactly how many skyscrapers there are. She begins at the leftmost skyscraper, with a counter at 1. She then moves to the right, one skyscraper at a time, adding 1 to her counter each time she moves. She continues until she reaches the rightmost skyscraper.Bob is impatient, and wants to finish as fast as possible. He begins at the leftmost skyscraper, with a counter at 1. He moves from building to building using zip lines. At each stage Bob uses the highest available zip line to the right, but ignores floors with a height greater than h due to fear of heights. When Bob uses a zip line, he travels too fast to count how many skyscrapers he passed. Instead, he just adds 2i to his counter, where i is the number of the floor he's currently on. He continues until he reaches the rightmost skyscraper.Consider the following example. There are 6 buildings, with heights 1, 4, 3, 4, 1, 2 from left to right, and h = 2. Alice begins with her counter at 1 and then adds 1 five times for a result of 6. Bob begins with his counter at 1, then he adds 1, 4, 4, and 2, in order, for a result of 12. Note that Bob ignores the highest zip line because of his fear of heights (h = 2).  Bob's counter is at the top of the image, and Alice's counter at the bottom. All zip lines are shown. Bob's path is shown by the green dashed line and Alice's by the pink dashed line. The floors of the skyscrapers are numbered, and the zip lines Bob uses are marked with the amount he adds to his counter.When Alice and Bob reach the right-most skyscraper, they compare counters. You will be given either the value of Alice's counter or the value of Bob's counter, and must compute the expected value of the other's counter.","['math', 'probabilities']","[0, 0, 0, 1, 0, 1, 0, 0]"784"Salem gave you $$$n$$$ sticks with integer positive lengths $$$a_1, a_2, \ldots, a_n$$$.For every stick, you can change its length to any other positive integer length (that is, either shrink or stretch it). The cost of changing the stick's length from $$$a$$$ to $$$b$$$ is $$$|a - b|$$$, where $$$|x|$$$ means the absolute value of $$$x$$$.A stick length $$$a_i$$$ is called almost good for some integer $$$t$$$ if $$$|a_i - t| \le 1$$$.Salem asks you to change the lengths of some sticks (possibly all or none), such that all sticks' lengths are almost good for some positive integer $$$t$$$ and the total cost of changing is minimum possible. The value of $$$t$$$ is not fixed in advance and you can choose it as any positive integer. As an answer, print the value of $$$t$$$ and the minimum cost. If there are multiple optimal choices for $$$t$$$, print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"785"Jeevan has two arrays $$$a$$$ and $$$b$$$ of size $$$n$$$. He is fond of performing weird operations on arrays. This time, he comes up with two types of operations:  Choose any $$$i$$$ ($$$1 \le i \le n$$$) and increment $$$a_j$$$ by $$$1$$$ for every $$$j$$$ which is a multiple of $$$i$$$ and $$$1 \le j \le n$$$.  Choose any $$$i$$$ ($$$1 \le i \le n$$$) and decrement $$$a_j$$$ by $$$1$$$ for every $$$j$$$ which is a multiple of $$$i$$$ and $$$1 \le j \le n$$$. He wants to convert array $$$a$$$ into an array $$$b$$$ using the minimum total number of operations. However, Jeevan seems to have forgotten the value of $$$b_1$$$. So he makes some guesses. He will ask you $$$q$$$ questions corresponding to his $$$q$$$ guesses, the $$$i$$$-th of which is of the form:   If $$$b_1 = x_i$$$, what is the minimum number of operations required to convert $$$a$$$ to $$$b$$$? Help him by answering each question.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"786"n fish, numbered from 1 to n, live in a lake. Every day right one pair of fish meet, and the probability of each other pair meeting is the same. If two fish with indexes i and j meet, the first will eat up the second with the probability aij, and the second will eat up the first with the probability aji = 1 - aij. The described process goes on until there are at least two fish in the lake. For each fish find out the probability that it will survive to be the last in the lake.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"787"This problem is same as the next one, but has smaller constraints.It was a Sunday morning when the three friends Selena, Shiro and Katie decided to have a trip to the nearby power station (do not try this at home). After arriving at the power station, the cats got impressed with a large power transmission system consisting of many chimneys, electric poles, and wires. Since they are cats, they found those things gigantic.At the entrance of the station, there is a map describing the complicated wiring system. Selena is the best at math among three friends. He decided to draw the map on the Cartesian plane. Each pole is now a point at some coordinates $$$(x_i, y_i)$$$. Since every pole is different, all of the points representing these poles are distinct. Also, every two poles are connected with each other by wires. A wire is a straight line on the plane infinite in both directions. If there are more than two poles lying on the same line, they are connected by a single common wire.Selena thinks, that whenever two different electric wires intersect, they may interfere with each other and cause damage. So he wonders, how many pairs are intersecting? Could you help him with this problem?",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"788"Real stupidity beats artificial intelligence every time.— Terry Pratchett, Hogfather, DiscworldYou are given a string $$$s$$$ of length $$$n$$$ and a number $$$k$$$. Let's denote by $$$rev(s)$$$ the reversed string $$$s$$$ (i.e. $$$rev(s) = s_n s_{n-1} ... s_1$$$). You can apply one of the two kinds of operations to the string: replace the string $$$s$$$ with $$$s + rev(s)$$$ replace the string $$$s$$$ with $$$rev(s) + s$$$How many different strings can you get as a result of performing exactly $$$k$$$ operations (possibly of different kinds) on the original string $$$s$$$?In this statement we denoted the concatenation of strings $$$s$$$ and $$$t$$$ as $$$s + t$$$. In other words, $$$s + t = s_1 s_2 ... s_n t_1 t_2 ... t_m$$$, where $$$n$$$ and $$$m$$$ are the lengths of strings $$$s$$$ and $$$t$$$ respectively.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"789"Max wants to buy a new skateboard. He has calculated the amount of money that is needed to buy a new skateboard. He left a calculator on the floor and went to ask some money from his parents. Meanwhile his little brother Yusuf came and started to press the keys randomly. Unfortunately Max has forgotten the number which he had calculated. The only thing he knows is that the number is divisible by 4.You are given a string s consisting of digits (the number on the display of the calculator after Yusuf randomly pressed the keys). Your task is to find the number of substrings which are divisible by 4. A substring can start with a zero.A substring of a string is a nonempty sequence of consecutive characters.For example if string s is 124 then we have four substrings that are divisible by 4: 12, 4, 24 and 124. For the string 04 the answer is three: 0, 4, 04.As input/output can reach huge size it is recommended to use fast input/output methods: for example, prefer to use gets/scanf/printf instead of getline/cin/cout in C++, prefer to use BufferedReader/PrintWriter instead of Scanner/System.out in Java.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"790"Jeff's got n cards, each card contains either digit 0, or digit 5. Jeff can choose several cards and put them in a line so that he gets some number. What is the largest possible number divisible by 90 Jeff can make from the cards he's got?Jeff must make the number without leading zero. At that, we assume that number 0 doesn't contain any leading zeroes. Jeff doesn't have to use all the cards.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"791"This is an interactive problem.Now Serval is a senior high school student in Japari Middle School. However, on the way to the school, he must go across a pond, in which there is a dangerous snake. The pond can be represented as a $$$n \times n$$$ grid. The snake has a head and a tail in different cells, and its body is a series of adjacent cells connecting the head and the tail without self-intersecting. If Serval hits its head or tail, the snake will bite him and he will die.Luckily, he has a special device which can answer the following question: you can pick a rectangle, it will tell you the number of times one needs to cross the border of the rectangle walking cell by cell along the snake from the head to the tail. The pictures below show a possible snake and a possible query to it, which will get an answer of $$$4$$$.    Today Serval got up too late and only have time to make $$$2019$$$ queries. As his best friend, can you help him find the positions of the head and the tail?Note that two cells are adjacent if and only if they have a common edge in the grid, and a snake can have a body of length $$$0$$$, that means it only has adjacent head and tail.Also note that the snake is sleeping, so it won't move while Serval using his device. And what's obvious is that the snake position does not depend on your queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"792"Nauuo is a girl who loves drawing circles.One day she has drawn a circle and wanted to draw a tree on it.The tree is a connected undirected graph consisting of $$$n$$$ nodes and $$$n-1$$$ edges. The nodes are numbered from $$$1$$$ to $$$n$$$.Nauuo wants to draw a tree on the circle, the nodes of the tree should be in $$$n$$$ distinct points on the circle, and the edges should be straight without crossing each other.""Without crossing each other"" means that every two edges have no common point or the only common point is an endpoint of both edges.Nauuo wants to draw the tree using a permutation of $$$n$$$ elements. A permutation of $$$n$$$ elements is a sequence of integers $$$p_1,p_2,\ldots,p_n$$$ in which every integer from $$$1$$$ to $$$n$$$ appears exactly once.After a permutation is chosen Nauuo draws the $$$i$$$-th node in the $$$p_i$$$-th point on the circle, then draws the edges connecting the nodes.The tree is given, Nauuo wants to know how many permutations are there so that the tree drawn satisfies the rule (the edges are straight without crossing each other). She only wants to know the answer modulo $$$998244353$$$, can you help her?It is obvious that whether a permutation is valid or not does not depend on which $$$n$$$ points on the circle are chosen.","['geometry', 'trees']","[0, 1, 0, 0, 0, 0, 0, 1]"793"This is an interactive problem.Given a simple undirected graph with $$$n$$$ vertices numbered from $$$1$$$ to $$$n$$$, your task is to color all the vertices such that for every color $$$c$$$, the following conditions hold:   The set of vertices with color $$$c$$$ is connected;  $$$s_c \leq n_c^2$$$, where $$$n_c$$$ is the number of vertices with color $$$c$$$, and $$$s_c$$$ is the sum of degrees of vertices with color $$$c$$$.  It can be shown that there always exists a way to color all the vertices such that the above conditions hold. Initially, you are only given the number $$$n$$$ of vertices and the degree of each vertex. In each query, you can choose a vertex $$$u$$$. As a response, you will be given the $$$k$$$-th edge incident to $$$u$$$, if this is the $$$k$$$-th query on vertex $$$u$$$. You are allowed to make at most $$$n$$$ queries.An undirected graph is simple if it does not contain multiple edges or self-loops.The degree of a vertex is the number of edges incident to it. A set $$$S$$$ of vertices is connected if for every two different vertices $$$u, v \in S$$$, there is a path, which only passes through vertices in $$$S$$$, that connects $$$u$$$ and $$$v$$$. That is, there is a sequence of edges $$$(u_1, v_1), (u_2, v_2), \dots, (u_k, v_k)$$$ with $$$k \geq 1$$$ such that   $$$u_1 = u$$$, $$$v_k = v$$$, and $$$v_i = u_{i+1}$$$ for every $$$1 \leq i < k$$$; and  $$$u_k \in S$$$ and $$$v_k \in S$$$ for every $$$1 \leq i \leq k$$$.  Especially, a set containing only one vertex is connected. ","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"794"Bob has a simple undirected connected graph (without self-loops and multiple edges). He wants to learn whether his graph is bipartite (that is, you can paint all vertices of the graph into two colors so that there is no edge connecting two vertices of the same color) or not. As he is not very good at programming, he asked Alice for help. He does not want to disclose his graph to Alice, but he agreed that Alice can ask him some questions about the graph.The only question that Alice can ask is the following: she sends $$$s$$$ — a subset of vertices of the original graph. Bob answers with the number of edges that have both endpoints in $$$s$$$. Since he doesn't want Alice to learn too much about the graph, he allows her to ask no more than $$$20000$$$ questions. Furthermore, he suspects that Alice might introduce false messages to their communication channel, so when Alice finally tells him whether the graph is bipartite or not, she also needs to provide a proof — either the partitions themselves or a cycle of odd length.Your task is to help Alice to construct the queries, find whether the graph is bipartite. ",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"795"It is lunch time for Mole. His friend, Marmot, prepared him a nice game for lunch.Marmot brought Mole n ordered piles of worms such that i-th pile contains ai worms. He labeled all these worms with consecutive integers: worms in first pile are labeled with numbers 1 to a1, worms in second pile are labeled with numbers a1 + 1 to a1 + a2 and so on. See the example for a better understanding.Mole can't eat all the worms (Marmot brought a lot) and, as we all know, Mole is blind, so Marmot tells him the labels of the best juicy worms. Marmot will only give Mole a worm if Mole says correctly in which pile this worm is contained.Poor Mole asks for your help. For all juicy worms said by Marmot, tell Mole the correct answers.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"796"Polycarpus participates in a competition for hacking into a new secure messenger. He's almost won.Having carefully studied the interaction protocol, Polycarpus came to the conclusion that the secret key can be obtained if he properly cuts the public key of the application into two parts. The public key is a long integer which may consist of even a million digits!Polycarpus needs to find such a way to cut the public key into two nonempty parts, that the first (left) part is divisible by a as a separate number, and the second (right) part is divisible by b as a separate number. Both parts should be positive integers that have no leading zeros. Polycarpus knows values a and b.Help Polycarpus and find any suitable method to cut the public key.","['math', 'number theory', 'strings']","[0, 0, 0, 1, 1, 0, 1, 0]"797"One day Vasya was solving arithmetical problems. He wrote down an expression a + b = c in his notebook. When the teacher checked Vasya's work it turned out that Vasya had solved the problem incorrectly. Now Vasya tries to find excuses. He says that he simply forgot to write down several digits in numbers a, b and c, but he can't remember what numbers they actually were. Help Vasya, find such numbers x, y and z, with which the following conditions are met:   x + y = z,  from the expression x + y = z several digits can be erased in such a way that the result will be a + b = c,  the expression x + y = z should have the minimal length. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"798"Shaass has decided to hunt some birds. There are n horizontal electricity wires aligned parallel to each other. Wires are numbered 1 to n from top to bottom. On each wire there are some oskols sitting next to each other. Oskol is the name of a delicious kind of birds in Shaass's territory. Supposed there are ai oskols sitting on the i-th wire.  Sometimes Shaass shots one of the birds and the bird dies (suppose that this bird sat at the i-th wire). Consequently all the birds on the i-th wire to the left of the dead bird get scared and jump up on the wire number i - 1, if there exists no upper wire they fly away. Also all the birds to the right of the dead bird jump down on wire number i + 1, if there exists no such wire they fly away. Shaass has shot m birds. You're given the initial number of birds on each wire, tell him how many birds are sitting on each wire after the shots.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"799"Learn, learn and learn again — Valera has to do this every day. He is studying at mathematical school, where math is the main discipline. The mathematics teacher loves her discipline very much and tries to cultivate this love in children. That's why she always gives her students large and difficult homework. Despite that Valera is one of the best students, he failed to manage with the new homework. That's why he asks for your help. He has the following task. A sequence of n numbers is given. A prefix of a sequence is the part of the sequence (possibly empty), taken from the start of the sequence. A suffix of a sequence is the part of the sequence (possibly empty), taken from the end of the sequence. It is allowed to sequentially make two operations with the sequence. The first operation is to take some prefix of the sequence and multiply all numbers in this prefix by  - 1. The second operation is to take some suffix and multiply all numbers in it by  - 1. The chosen prefix and suffix may intersect. What is the maximum total sum of the sequence that can be obtained by applying the described operations?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"800"A new innovative ticketing systems for public transport is introduced in Bytesburg. Now there is a single travel card for all transport. To make a trip a passenger scan his card and then he is charged according to the fare.The fare is constructed in the following manner. There are three types of tickets:   a ticket for one trip costs 20 byteland rubles,  a ticket for 90 minutes costs 50 byteland rubles,  a ticket for one day (1440 minutes) costs 120 byteland rubles. Note that a ticket for x minutes activated at time t can be used for trips started in time range from t to t + x - 1, inclusive. Assume that all trips take exactly one minute.To simplify the choice for the passenger, the system automatically chooses the optimal tickets. After each trip starts, the system analyses all the previous trips and the current trip and chooses a set of tickets for these trips with a minimum total cost. Let the minimum total cost of tickets to cover all trips from the first to the current is a, and the total sum charged before is b. Then the system charges the passenger the sum a - b.You have to write a program that, for given trips made by a passenger, calculates the sum the passenger is charged after each trip.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"801"In Berland, $$$n$$$ different types of banknotes are used. Banknotes of the $$$i$$$-th type have denomination $$$10^{a_i}$$$ burles (burles are the currency used in Berland); the denomination of banknotes of the first type is exactly $$$1$$$.Let's denote $$$f(s)$$$ as the minimum number of banknotes required to represent exactly $$$s$$$ burles. For example, if the denominations of banknotes used in Berland are $$$1$$$, $$$10$$$ and $$$100$$$, then $$$f(59) = 14$$$: $$$9$$$ banknotes with denomination of $$$1$$$ burle and $$$5$$$ banknotes with denomination of $$$10$$$ burles can be used to represent exactly $$$9 \cdot 1 + 5 \cdot 10 = 59$$$ burles, and there's no way to do it with fewer banknotes.For a given integer $$$k$$$, find the minimum positive number of burles $$$s$$$ that cannot be represented with $$$k$$$ or fewer banknotes (that is, $$$f(s) > k$$$).",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"802"This is an interactive problem. The only difference between the easy and hard version is the limit on number of questions.There are $$$n$$$ players labelled from $$$1$$$ to $$$n$$$. It is guaranteed that $$$n$$$ is a multiple of $$$3$$$.Among them, there are $$$k$$$ impostors and $$$n-k$$$ crewmates. The number of impostors, $$$k$$$, is not given to you. It is guaranteed that $$$\frac{n}{3} < k < \frac{2n}{3}$$$.In each question, you can choose three distinct integers $$$a$$$, $$$b$$$, $$$c$$$ ($$$1 \le a, b, c \le n$$$) and ask: ""Among the players labelled $$$a$$$, $$$b$$$ and $$$c$$$, are there more impostors or more crewmates?"" You will be given the integer $$$0$$$ if there are more impostors than crewmates, and $$$1$$$ otherwise.Find the number of impostors $$$k$$$ and the indices of players that are impostors after asking at most $$$n+6$$$ questions.The jury is adaptive, which means the indices of impostors may not be fixed beforehand and can depend on your questions. It is guaranteed that there is at least one set of impostors which fulfills the constraints and the answers to your questions at any time.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"803"Danny, the local Math Maniac, is fascinated by circles, Omkar's most recent creation. Help him solve this circle problem!You are given $$$n$$$ nonnegative integers $$$a_1, a_2, \dots, a_n$$$ arranged in a circle, where $$$n$$$ must be odd (ie. $$$n-1$$$ is divisible by $$$2$$$). Formally, for all $$$i$$$ such that $$$2 \leq i \leq n$$$, the elements $$$a_{i - 1}$$$ and $$$a_i$$$ are considered to be adjacent, and $$$a_n$$$ and $$$a_1$$$ are also considered to be adjacent. In one operation, you pick a number on the circle, replace it with the sum of the two elements adjacent to it, and then delete the two adjacent elements from the circle. This is repeated until only one number remains in the circle, which we call the circular value.Help Danny find the maximum possible circular value after some sequences of operations. ",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"804"You are given $$$n$$$ numbers $$$a_1, a_2, \dots, a_n$$$. With a cost of one coin you can perform the following operation:Choose one of these numbers and add or subtract $$$1$$$ from it.In particular, we can apply this operation to the same number several times.We want to make the product of all these numbers equal to $$$1$$$, in other words, we want $$$a_1 \cdot a_2$$$ $$$\dots$$$ $$$\cdot a_n = 1$$$. For example, for $$$n = 3$$$ and numbers $$$[1, -3, 0]$$$ we can make product equal to $$$1$$$ in $$$3$$$ coins: add $$$1$$$ to second element, add $$$1$$$ to second element again, subtract $$$1$$$ from third element, so that array becomes $$$[1, -1, -1]$$$. And $$$1\cdot (-1) \cdot (-1) = 1$$$.What is the minimum cost we will have to pay to do that?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"805"This is the hard version of the problem. The only difference between the easy version and the hard version is the constraints on $$$n$$$. You can only make hacks if both versions are solved.A permutation of $$$1, 2, \ldots, n$$$ is a sequence of $$$n$$$ integers, where each integer from $$$1$$$ to $$$n$$$ appears exactly once. For example, $$$[2,3,1,4]$$$ is a permutation of $$$1, 2, 3, 4$$$, but $$$[1,4,2,2]$$$ isn't because $$$2$$$ appears twice in it.Recall that the number of inversions in a permutation $$$a_1, a_2, \ldots, a_n$$$ is the number of pairs of indices $$$(i, j)$$$ such that $$$i < j$$$ and $$$a_i > a_j$$$.Let $$$p$$$ and $$$q$$$ be two permutations of $$$1, 2, \ldots, n$$$. Find the number of permutation pairs $$$(p,q)$$$ that satisfy the following conditions:  $$$p$$$ is lexicographically smaller than $$$q$$$.  the number of inversions in $$$p$$$ is greater than the number of inversions in $$$q$$$. Print the number of such pairs modulo $$$mod$$$. Note that $$$mod$$$ may not be a prime.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"806"A widely known among some people Belarusian sport programmer Lesha decided to make some money to buy a one square meter larger flat. To do this, he wants to make and carry out a Super Rated Match (SRM) on the site Torcoder.com. But there's a problem — a severe torcoder coordinator Ivan does not accept any Lesha's problem, calling each of them an offensive word ""duped"" (that is, duplicated). And one day they nearely quarrelled over yet another problem Ivan wouldn't accept.You are invited to act as a fair judge and determine whether the problem is indeed brand new, or Ivan is right and the problem bears some resemblance to those used in the previous SRMs.You are given the descriptions of Lesha's problem and each of Torcoder.com archive problems. The description of each problem is a sequence of words. Besides, it is guaranteed that Lesha's problem has no repeated words, while the description of an archive problem may contain any number of repeated words.The ""similarity"" between Lesha's problem and some archive problem can be found as follows. Among all permutations of words in Lesha's problem we choose the one that occurs in the archive problem as a subsequence. If there are multiple such permutations, we choose the one with the smallest number of inversions. Then the ""similarity"" of a problem can be written as , where n is the number of words in Lesha's problem and x is the number of inversions in the chosen permutation. Note that the ""similarity"" p is always a positive integer.The problem is called brand new if there is not a single problem in Ivan's archive which contains a permutation of words from Lesha's problem as a subsequence.Help the boys and determine whether the proposed problem is new, or specify the problem from the archive which resembles Lesha's problem the most, otherwise.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"807"Petya works as a PR manager for a successful Berland company BerSoft. He needs to prepare a presentation on the company income growth since 2001 (the year of its founding) till now. Petya knows that in 2001 the company income amounted to a1 billion bourles, in 2002 — to a2 billion, ..., and in the current (2000 + n)-th year — an billion bourles. On the base of the information Petya decided to show in his presentation the linear progress history which is in his opinion perfect. According to a graph Petya has already made, in the first year BerSoft company income must amount to 1 billion bourles, in the second year — 2 billion bourles etc., each following year the income increases by 1 billion bourles. Unfortunately, the real numbers are different from the perfect ones. Among the numbers ai can even occur negative ones that are a sign of the company’s losses in some years. That is why Petya wants to ignore some data, in other words, cross some numbers ai from the sequence and leave only some subsequence that has perfect growth.Thus Petya has to choose a sequence of years y1, y2, ..., yk,so that in the year y1 the company income amounted to 1 billion bourles, in the year y2 — 2 billion bourles etc., in accordance with the perfect growth dynamics. Help him to choose the longest such sequence.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"808"As Famil Door’s birthday is coming, some of his friends (like Gabi) decided to buy a present for him. His friends are going to buy a string consisted of round brackets since Famil Door loves string of brackets of length n more than any other strings!The sequence of round brackets is called valid if and only if:   the total number of opening brackets is equal to the total number of closing brackets;  for any prefix of the sequence, the number of opening brackets is greater or equal than the number of closing brackets. Gabi bought a string s of length m (m ≤ n) and want to complete it to obtain a valid sequence of brackets of length n. He is going to pick some strings p and q consisting of round brackets and merge them in a string p + s + q, that is add the string p at the beginning of the string s and string q at the end of the string s.Now he wonders, how many pairs of strings p and q exists, such that the string p + s + q is a valid sequence of round brackets. As this number may be pretty large, he wants to calculate it modulo 109 + 7.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"809"Berland has n cities, some of them are connected by bidirectional roads. For each road we know whether it is asphalted or not.The King of Berland Valera II wants to asphalt all roads of Berland, for that he gathered a group of workers. Every day Valera chooses exactly one city and orders the crew to asphalt all roads that come from the city. The valiant crew fulfilled the King's order in a day, then workers went home.Unfortunately, not everything is as great as Valera II would like. The main part of the group were gastarbeiters — illegal immigrants who are enthusiastic but not exactly good at understanding orders in Berlandian. Therefore, having received orders to asphalt the roads coming from some of the city, the group asphalted all non-asphalted roads coming from the city, and vice versa, took the asphalt from the roads that had it.Upon learning of this progress, Valera II was very upset, but since it was too late to change anything, he asked you to make a program that determines whether you can in some way asphalt Berlandian roads in at most n days. Help the king.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"810"This is the hard version of the problem. The difference between the versions is that the easy version has no swap operations. You can make hacks only if all versions of the problem are solved.Pikachu is a cute and friendly pokémon living in the wild pikachu herd.But it has become known recently that infamous team R wanted to steal all these pokémon! Pokémon trainer Andrew decided to help Pikachu to build a pokémon army to resist.First, Andrew counted all the pokémon — there were exactly $$$n$$$ pikachu. The strength of the $$$i$$$-th pokémon is equal to $$$a_i$$$, and all these numbers are distinct.As an army, Andrew can choose any non-empty subsequence of pokemons. In other words, Andrew chooses some array $$$b$$$ from $$$k$$$ indices such that $$$1 \le b_1 < b_2 < \dots < b_k \le n$$$, and his army will consist of pokémons with forces $$$a_{b_1}, a_{b_2}, \dots, a_{b_k}$$$.The strength of the army is equal to the alternating sum of elements of the subsequence; that is, $$$a_{b_1} - a_{b_2} + a_{b_3} - a_{b_4} + \dots$$$.Andrew is experimenting with pokémon order. He performs $$$q$$$ operations. In $$$i$$$-th operation Andrew swaps $$$l_i$$$-th and $$$r_i$$$-th pokémon.Andrew wants to know the maximal stregth of the army he can achieve with the initial pokémon placement. He also needs to know the maximal strength after each operation.Help Andrew and the pokémon, or team R will realize their tricky plan!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"811"Polycarp has three sisters: Alice, Barbara, and Cerene. They're collecting coins. Currently, Alice has $$$a$$$ coins, Barbara has $$$b$$$ coins and Cerene has $$$c$$$ coins. Recently Polycarp has returned from the trip around the world and brought $$$n$$$ coins.He wants to distribute all these $$$n$$$ coins between his sisters in such a way that the number of coins Alice has is equal to the number of coins Barbara has and is equal to the number of coins Cerene has. In other words, if Polycarp gives $$$A$$$ coins to Alice, $$$B$$$ coins to Barbara and $$$C$$$ coins to Cerene ($$$A+B+C=n$$$), then $$$a + A = b + B = c + C$$$.Note that A, B or C (the number of coins Polycarp gives to Alice, Barbara and Cerene correspondingly) can be 0.Your task is to find out if it is possible to distribute all $$$n$$$ coins between sisters in a way described above.You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"812"There was a big bank robbery in Tablecity. In order to catch the thief, the President called none other than Albert – Tablecity’s Chief of Police. Albert does not know where the thief is located, but he does know how he moves.Tablecity can be represented as 1000 × 2 grid, where every cell represents one district. Each district has its own unique name “(X, Y)”, where X and Y are the coordinates of the district in the grid. The thief’s movement is as Every hour the thief will leave the district (X, Y) he is currently hiding in, and move to one of the districts: (X - 1, Y), (X + 1, Y), (X - 1, Y - 1), (X - 1, Y + 1), (X + 1, Y - 1), (X + 1, Y + 1) as long as it exists in Tablecity. Below is an example of thief’s possible movements if he is located in district (7,1):Albert has enough people so that every hour he can pick any two districts in Tablecity and fully investigate them, making sure that if the thief is located in one of them, he will get caught. Albert promised the President that the thief will be caught in no more than 2015 hours and needs your help in order to achieve that.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"813"You are given a string s, consisting of small Latin letters. Let's denote the length of the string as |s|. The characters in the string are numbered starting from 1. Your task is to find out if it is possible to rearrange characters in string s so that for any prime number p ≤ |s| and for any integer i ranging from 1 to |s| / p (inclusive) the following condition was fulfilled sp = sp × i. If the answer is positive, find one way to rearrange the characters.","['number theory', 'strings']","[0, 0, 0, 0, 1, 0, 1, 0]"814"After the war, the supersonic rocket became the most common public transportation.Each supersonic rocket consists of two ""engines"". Each engine is a set of ""power sources"". The first engine has $$$n$$$ power sources, and the second one has $$$m$$$ power sources. A power source can be described as a point $$$(x_i, y_i)$$$ on a 2-D plane. All points in each engine are different.You can manipulate each engine separately. There are two operations that you can do with each engine. You can do each operation as many times as you want. For every power source as a whole in that engine: $$$(x_i, y_i)$$$ becomes $$$(x_i+a, y_i+b)$$$, $$$a$$$ and $$$b$$$ can be any real numbers. In other words, all power sources will be shifted. For every power source as a whole in that engine: $$$(x_i, y_i)$$$ becomes $$$(x_i \cos \theta - y_i \sin \theta, x_i \sin \theta + y_i \cos \theta)$$$, $$$\theta$$$ can be any real number. In other words, all power sources will be rotated.The engines work as follows: after the two engines are powered, their power sources are being combined (here power sources of different engines may coincide). If two power sources $$$A(x_a, y_a)$$$ and $$$B(x_b, y_b)$$$ exist, then for all real number $$$k$$$ that $$$0 \lt k \lt 1$$$, a new power source will be created $$$C_k(kx_a+(1-k)x_b,ky_a+(1-k)y_b)$$$. Then, this procedure will be repeated again with all new and old power sources. After that, the ""power field"" from all power sources will be generated (can be considered as an infinite set of all power sources occurred).A supersonic rocket is ""safe"" if and only if after you manipulate the engines, destroying any power source and then power the engine, the power field generated won't be changed (comparing to the situation where no power source erased). Two power fields are considered the same if and only if any power source in one field belongs to the other one as well.Given a supersonic rocket, check whether it is safe or not.","['geometry', 'strings']","[0, 1, 0, 0, 0, 0, 1, 0]"815"Ayoub thinks that he is a very smart person, so he created a function $$$f(s)$$$, where $$$s$$$ is a binary string (a string which contains only symbols ""0"" and ""1""). The function $$$f(s)$$$ is equal to the number of substrings in the string $$$s$$$ that contains at least one symbol, that is equal to ""1"".More formally, $$$f(s)$$$ is equal to the number of pairs of integers $$$(l, r)$$$, such that $$$1 \leq l \leq r \leq |s|$$$ (where $$$|s|$$$ is equal to the length of string $$$s$$$), such that at least one of the symbols $$$s_l, s_{l+1}, \ldots, s_r$$$ is equal to ""1"". For example, if $$$s = $$$""01010"" then $$$f(s) = 12$$$, because there are $$$12$$$ such pairs $$$(l, r)$$$: $$$(1, 2), (1, 3), (1, 4), (1, 5), (2, 2), (2, 3), (2, 4), (2, 5), (3, 4), (3, 5), (4, 4), (4, 5)$$$.Ayoub also thinks that he is smarter than Mahmoud so he gave him two integers $$$n$$$ and $$$m$$$ and asked him this problem. For all binary strings $$$s$$$ of length $$$n$$$ which contains exactly $$$m$$$ symbols equal to ""1"", find the maximum value of $$$f(s)$$$.Mahmoud couldn't solve the problem so he asked you for help. Can you help him? ","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"816"You are given a string $$$s$$$ of length $$$n$$$, which consists only of the first $$$k$$$ letters of the Latin alphabet. All letters in string $$$s$$$ are uppercase.A subsequence of string $$$s$$$ is a string that can be derived from $$$s$$$ by deleting some of its symbols without changing the order of the remaining symbols. For example, ""ADE"" and ""BD"" are subsequences of ""ABCDE"", but ""DEA"" is not.A subsequence of $$$s$$$ called good if the number of occurences of each of the first $$$k$$$ letters of the alphabet is the same.Find the length of the longest good subsequence of $$$s$$$. ",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"817"You are given a string A. Find a string B, where B is a palindrome and A is a subsequence of B.A subsequence of a string is a string that can be derived from it by deleting some (not necessarily consecutive) characters without changing the order of the remaining characters. For example, ""cotst"" is a subsequence of ""contest"".A palindrome is a string that reads the same forward or backward.The length of string B should be at most 104. It is guaranteed that there always exists such string.You do not need to find the shortest answer, the only restriction is that the length of string B should not exceed 104.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"818"Dima has a hamsters farm. Soon N hamsters will grow up on it and Dima will sell them in a city nearby.Hamsters should be transported in boxes. If some box is not completely full, the hamsters in it are bored, that's why each box should be completely full with hamsters.Dima can buy boxes at a factory. The factory produces boxes of K kinds, boxes of the i-th kind can contain in themselves ai hamsters. Dima can buy any amount of boxes, but he should buy boxes of only one kind to get a wholesale discount.Of course, Dima would buy boxes in such a way that each box can be completely filled with hamsters and transported to the city. If there is no place for some hamsters, Dima will leave them on the farm.Find out how many boxes and of which type should Dima buy to transport maximum number of hamsters.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"819"Alfred wants to buy a toy moose that costs c dollars. The store doesn’t give change, so he must give the store exactly c dollars, no more and no less. He has n coins. To make c dollars from his coins, he follows the following algorithm: let S be the set of coins being used. S is initially empty. Alfred repeatedly adds to S the highest-valued coin he has such that the total value of the coins in S after adding the coin doesn’t exceed c. If there is no such coin, and the value of the coins in S is still less than c, he gives up and goes home. Note that Alfred never removes a coin from S after adding it.As a programmer, you might be aware that Alfred’s algorithm can fail even when there is a set of coins with value exactly c. For example, if Alfred has one coin worth $3, one coin worth $4, and two coins worth $5, and the moose costs $12, then Alfred will add both of the $5 coins to S and then give up, since adding any other coin would cause the value of the coins in S to exceed $12. Of course, Alfred could instead combine one $3 coin, one $4 coin, and one $5 coin to reach the total.Bob tried to convince Alfred that his algorithm was flawed, but Alfred didn’t believe him. Now Bob wants to give Alfred some coins (in addition to those that Alfred already has) such that Alfred’s algorithm fails. Bob can give Alfred any number of coins of any denomination (subject to the constraint that each coin must be worth a positive integer number of dollars). There can be multiple coins of a single denomination. He would like to minimize the total value of the coins he gives Alfred. Please find this minimum value. If there is no solution, print ""Greed is good"". You can assume that the answer, if it exists, is positive. In other words, Alfred's algorithm will work if Bob doesn't give him any coins.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"820"You are given an array $$$a$$$ consisting of $$$n$$$ integers. Beauty of array is the maximum sum of some consecutive subarray of this array (this subarray may be empty). For example, the beauty of the array [10, -5, 10, -4, 1] is 15, and the beauty of the array [-3, -5, -1] is 0.You may choose at most one consecutive subarray of $$$a$$$ and multiply all values contained in this subarray by $$$x$$$. You want to maximize the beauty of array after applying at most one such operation.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"821"Nauuo is a girl who loves playing cards.One day she was playing cards but found that the cards were mixed with some empty ones.There are $$$n$$$ cards numbered from $$$1$$$ to $$$n$$$, and they were mixed with another $$$n$$$ empty cards. She piled up the $$$2n$$$ cards and drew $$$n$$$ of them. The $$$n$$$ cards in Nauuo's hands are given. The remaining $$$n$$$ cards in the pile are also given in the order from top to bottom.In one operation she can choose a card in her hands and play it — put it at the bottom of the pile, then draw the top card from the pile.Nauuo wants to make the $$$n$$$ numbered cards piled up in increasing order (the $$$i$$$-th card in the pile from top to bottom is the card $$$i$$$) as quickly as possible. Can you tell her the minimum number of operations?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"822"As you could know there are no male planes nor female planes. However, each plane on Earth likes some other plane. There are n planes on Earth, numbered from 1 to n, and the plane with number i likes the plane with number fi, where 1 ≤ fi ≤ n and fi ≠ i.We call a love triangle a situation in which plane A likes plane B, plane B likes plane C and plane C likes plane A. Find out if there is any love triangle on Earth.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"823"Don't you tell me what you think that I can beIf you say that Arkady is a bit old-fashioned playing checkers, you won't be right. There is also a modern computer game Arkady and his friends are keen on. We won't discuss its rules, the only feature important to this problem is that each player has to pick a distinct hero in the beginning of the game.There are $$$2$$$ teams each having $$$n$$$ players and $$$2n$$$ heroes to distribute between the teams. The teams take turns picking heroes: at first, the first team chooses a hero in its team, after that the second team chooses a hero and so on. Note that after a hero is chosen it becomes unavailable to both teams.The friends estimate the power of the $$$i$$$-th of the heroes as $$$p_i$$$. Each team wants to maximize the total power of its heroes. However, there is one exception: there are $$$m$$$ pairs of heroes that are especially strong against each other, so when any team chooses a hero from such a pair, the other team must choose the other one on its turn. Each hero is in at most one such pair.This is an interactive problem. You are to write a program that will optimally choose the heroes for one team, while the jury's program will play for the other team. Note that the jury's program may behave inefficiently, in this case you have to take the opportunity and still maximize the total power of your team. Formally, if you ever have chance to reach the total power of $$$q$$$ or greater regardless of jury's program choices, you must get $$$q$$$ or greater to pass a test.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"824"International Women's Day is coming soon! Polycarp is preparing for the holiday.There are $$$n$$$ candy boxes in the shop for sale. The $$$i$$$-th box contains $$$d_i$$$ candies.Polycarp wants to prepare the maximum number of gifts for $$$k$$$ girls. Each gift will consist of exactly two boxes. The girls should be able to share each gift equally, so the total amount of candies in a gift (in a pair of boxes) should be divisible by $$$k$$$. In other words, two boxes $$$i$$$ and $$$j$$$ ($$$i \ne j$$$) can be combined as a gift if $$$d_i + d_j$$$ is divisible by $$$k$$$.How many boxes will Polycarp be able to give? Of course, each box can be a part of no more than one gift. Polycarp cannot use boxes ""partially"" or redistribute candies between them. ","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"825"A lot of students spend their winter holidays productively. Vlad has advanced very well in doing so! For three days already, fueled by salads and tangerines — the leftovers from New Year celebration — he has been calibrating his rating in his favorite MOBA game, playing as a hero named Perun.Perun has an ultimate ability called ""Thunderwrath"". At the instant of its activation, each enemy on the map (n of them in total) loses  health points as a single-time effect. It also has a restriction: it can only activated when the moment of time is an integer. The initial bounty for killing an enemy is . Additionally, it increases by  each second. Formally, if at some second t the ability is activated and the i-th enemy is killed as a result (i.e. his health drops to zero or lower), Vlad earns  units of gold.Every enemy can receive damage, as well as be healed. There are multiple ways of doing so, but Vlad is not interested in details. For each of n enemies he knows:    — maximum number of health points for the i-th enemy;   — initial health of the enemy (on the 0-th second);   — the amount of health the i-th enemy can regenerate per second. There also m health updates Vlad knows about:    — time when the health was updated;   — the enemy whose health was updated;   — updated health points for enemyj. Obviously, Vlad wants to maximize his profit. If it's necessary, he could even wait for years to activate his ability at the right second. Help him determine the exact second (note that it must be an integer) from 0 (inclusively) to  + ∞ so that a single activation of the ability would yield Vlad the maximum possible amount of gold, and print this amount.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"826"One day Nikita found the string containing letters ""a"" and ""b"" only. Nikita thinks that string is beautiful if it can be cut into 3 strings (possibly empty) without changing the order of the letters, where the 1-st and the 3-rd one contain only letters ""a"" and the 2-nd contains only letters ""b"".Nikita wants to make the string beautiful by removing some (possibly none) of its characters, but without changing their order. What is the maximum length of the string he can get?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"827"You are given an undirected graph with $$$n$$$ vertices and $$$m$$$ edges. Also, you are given an integer $$$k$$$.Find either a clique of size $$$k$$$ or a non-empty subset of vertices such that each vertex of this subset has at least $$$k$$$ neighbors in the subset. If there are no such cliques and subsets report about it.A subset of vertices is called a clique of size $$$k$$$ if its size is $$$k$$$ and there exists an edge between every two vertices from the subset. A vertex is called a neighbor of the other vertex if there exists an edge between them.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"828"Dark is going to attend Motarack's birthday. Dark decided that the gift he is going to give to Motarack is an array $$$a$$$ of $$$n$$$ non-negative integers.Dark created that array $$$1000$$$ years ago, so some elements in that array disappeared. Dark knows that Motarack hates to see an array that has two adjacent elements with a high absolute difference between them. He doesn't have much time so he wants to choose an integer $$$k$$$ ($$$0 \leq k \leq 10^{9}$$$) and replaces all missing elements in the array $$$a$$$ with $$$k$$$.Let $$$m$$$ be the maximum absolute difference between all adjacent elements (i.e. the maximum value of $$$|a_i - a_{i+1}|$$$ for all $$$1 \leq i \leq n - 1$$$) in the array $$$a$$$ after Dark replaces all missing elements with $$$k$$$.Dark should choose an integer $$$k$$$ so that $$$m$$$ is minimized. Can you help him?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"829"Imp is really pleased that you helped him. But it you solve the last problem, his gladness would raise even more.   Let's define  for some set of integers  as the number of pairs a, b in , such that:  a is strictly less than b;  a divides b without a remainder. You are to find such a set , which is a subset of {1, 2, ..., n} (the set that contains all positive integers not greater than n), that . ",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"830"Twilight Sparkle once got a crystal from the Crystal Mine. A crystal of size n (n is odd; n > 1) is an n × n matrix with a diamond inscribed into it.You are given an odd integer n. You need to draw a crystal of size n. The diamond cells of the matrix should be represented by character ""D"". All other cells of the matrix should be represented by character ""*"". Look at the examples to understand what you need to draw.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"831"The administration of the Tomsk Region firmly believes that it's time to become a megacity (that is, get population of one million). Instead of improving the demographic situation, they decided to achieve its goal by expanding the boundaries of the city.The city of Tomsk can be represented as point on the plane with coordinates (0; 0). The city is surrounded with n other locations, the i-th one has coordinates (xi, yi) with the population of ki people. You can widen the city boundaries to a circle of radius r. In such case all locations inside the circle and on its border are included into the city.Your goal is to write a program that will determine the minimum radius r, to which is necessary to expand the boundaries of Tomsk, so that it becomes a megacity.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"832"Dima the hamster enjoys nibbling different things: cages, sticks, bad problemsetters and even trees!Recently he found a binary search tree and instinctively nibbled all of its edges, hence messing up the vertices. Dima knows that if Andrew, who has been thoroughly assembling the tree for a long time, comes home and sees his creation demolished, he'll get extremely upset. To not let that happen, Dima has to recover the binary search tree. Luckily, he noticed that any two vertices connected by a direct edge had their greatest common divisor value exceed $$$1$$$.Help Dima construct such a binary search tree or determine that it's impossible. The definition and properties of a binary search tree can be found here.","['math', 'number theory', 'trees']","[0, 0, 0, 1, 1, 0, 0, 1]"833"Let's call the following process a transformation of a sequence of length $$$n$$$.If the sequence is empty, the process ends. Otherwise, append the greatest common divisor (GCD) of all the elements of the sequence to the result and remove one arbitrary element from the sequence. Thus, when the process ends, we have a sequence of $$$n$$$ integers: the greatest common divisors of all the elements in the sequence before each deletion.You are given an integer sequence $$$1, 2, \dots, n$$$. Find the lexicographically maximum result of its transformation.A sequence $$$a_1, a_2, \ldots, a_n$$$ is lexicographically larger than a sequence $$$b_1, b_2, \ldots, b_n$$$, if there is an index $$$i$$$ such that $$$a_j = b_j$$$ for all $$$j < i$$$, and $$$a_i > b_i$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"834"Polygon is not only the best platform for developing problems but also a square matrix with side $$$n$$$, initially filled with the character 0.On the polygon, military training was held. The soldiers placed a cannon above each cell in the first row and a cannon to the left of each cell in the first column. Thus, exactly $$$2n$$$ cannons were placed.    Initial polygon for $$$n=4$$$. Cannons shoot character 1. At any moment of time, no more than one cannon is shooting. When a 1 flies out of a cannon, it flies forward (in the direction of the shot) until it collides with a polygon border or another 1. After that, it takes the cell in which it was before the collision and remains there. Take a look at the examples for better understanding.More formally:   if a cannon stands in the row $$$i$$$, to the left of the first column, and shoots with a 1, then the 1 starts its flight from the cell ($$$i, 1$$$) and ends in some cell ($$$i, j$$$);  if a cannon stands in the column $$$j$$$, above the first row, and shoots with a 1, then the 1 starts its flight from the cell ($$$1, j$$$) and ends in some cell ($$$i, j$$$). For example, consider the following sequence of shots:   1. Shoot the cannon in the row $$$2$$$.                         2. Shoot the cannon in the row $$$2$$$.                         3. Shoot the cannon in column $$$3$$$. You have a report from the military training on your desk. This report is a square matrix with side length $$$n$$$ consisting of 0 and 1. You wonder if the training actually happened. In other words, is there a sequence of shots such that, after the training, you get the given matrix?Each cannon can make an arbitrary number of shots. Before the training, each cell of the polygon contains 0.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"835"It's holiday. Mashmokh and his boss, Bimokh, are playing a game invented by Mashmokh. In this game Mashmokh writes sequence of n distinct integers on the board. Then Bimokh makes several (possibly zero) moves. On the first move he removes the first and the second integer from from the board, on the second move he removes the first and the second integer of the remaining sequence from the board, and so on. Bimokh stops when the board contains less than two numbers. When Bimokh removes numbers x and y from the board, he gets gcd(x, y) points. At the beginning of the game Bimokh has zero points.Mashmokh wants to win in the game. For this reason he wants his boss to get exactly k points in total. But the guy doesn't know how choose the initial sequence in the right way. Please, help him. Find n distinct integers a1, a2, ..., an such that his boss will score exactly k points. Also Mashmokh can't memorize too huge numbers. Therefore each of these integers must be at most 109.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"836"Andrew, Fedor and Alex are inventive guys. Now they invent the game with strings for two players.Given a group of n non-empty strings. During the game two players build the word together, initially the word is empty. The players move in turns. On his step player must add a single letter in the end of the word, the resulting word must be prefix of at least one string from the group. A player loses if he cannot move.Andrew and Alex decided to play this game k times. The player who is the loser of the i-th game makes the first move in the (i + 1)-th game. Guys decided that the winner of all games is the player who wins the last (k-th) game. Andrew and Alex already started the game. Fedor wants to know who wins the game if both players will play optimally. Help him.","['games', 'strings', 'trees']","[1, 0, 0, 0, 0, 0, 1, 1]"837"Danil decided to earn some money, so he had found a part-time job. The interview have went well, so now he is a light switcher.Danil works in a rooted tree (undirected connected acyclic graph) with n vertices, vertex 1 is the root of the tree. There is a room in each vertex, light can be switched on or off in each room. Danil's duties include switching light in all rooms of the subtree of the vertex. It means that if light is switched on in some room of the subtree, he should switch it off. Otherwise, he should switch it on.Unfortunately (or fortunately), Danil is very lazy. He knows that his boss is not going to personally check the work. Instead, he will send Danil tasks using Workforces personal messages.There are two types of tasks:  pow v describes a task to switch lights in the subtree of vertex v. get v describes a task to count the number of rooms in the subtree of v, in which the light is turned on. Danil should send the answer to his boss using Workforces messages.A subtree of vertex v is a set of vertices for which the shortest path from them to the root passes through v. In particular, the vertex v is in the subtree of v.Danil is not going to perform his duties. He asks you to write a program, which answers the boss instead of him.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"838"Consider the infinite sequence $$$s$$$ of positive integers, created by repeating the following steps:  Find the lexicographically smallest triple of positive integers $$$(a, b, c)$$$ such that   $$$a \oplus b \oplus c = 0$$$, where $$$\oplus$$$ denotes the bitwise XOR operation.  $$$a$$$, $$$b$$$, $$$c$$$ are not in $$$s$$$.  Here triple of integers $$$(a_1, b_1, c_1)$$$ is considered to be lexicographically smaller than triple $$$(a_2, b_2, c_2)$$$ if sequence $$$[a_1, b_1, c_1]$$$ is lexicographically smaller than sequence $$$[a_2, b_2, c_2]$$$.  Append $$$a$$$, $$$b$$$, $$$c$$$ to $$$s$$$ in this order.  Go back to the first step. You have integer $$$n$$$. Find the $$$n$$$-th element of $$$s$$$.You have to answer $$$t$$$ independent test cases.A sequence $$$a$$$ is lexicographically smaller than a sequence $$$b$$$ if in the first position where $$$a$$$ and $$$b$$$ differ, the sequence $$$a$$$ has a smaller element than the corresponding element in $$$b$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"839"A sequence of $$$n$$$ integers is called a permutation if it contains all integers from $$$1$$$ to $$$n$$$ exactly once.Given two integers $$$n$$$ and $$$k$$$, construct a permutation $$$a$$$ of numbers from $$$1$$$ to $$$n$$$ which has exactly $$$k$$$ peaks. An index $$$i$$$ of an array $$$a$$$ of size $$$n$$$ is said to be a peak if $$$1 < i < n$$$ and $$$a_i \gt a_{i-1}$$$ and $$$a_i \gt a_{i+1}$$$. If such permutation is not possible, then print $$$-1$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"840"Mr. F has $$$n$$$ positive integers, $$$a_1, a_2, \ldots, a_n$$$.He thinks the greatest common divisor of these integers is too small. So he wants to enlarge it by removing some of the integers.But this problem is too simple for him, so he does not want to do it by himself. If you help him, he will give you some scores in reward.Your task is to calculate the minimum number of integers you need to remove so that the greatest common divisor of the remaining integers is bigger than that of all integers.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"841"A teacher decides to give toffees to his students. He asks n students to stand in a queue. Since the teacher is very partial, he follows the following rule to distribute toffees.He looks at the first two students and gives more toffees to the student having higher marks than the other one. If they have the same marks they get the same number of toffees. The same procedure is followed for each pair of adjacent students starting from the first one to the last one.It is given that each student receives at least one toffee. You have to find the number of toffees given to each student by the teacher such that the total number of toffees is minimum.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"842"According to rules of the Berland fashion, a jacket should be fastened by all the buttons except only one, but not necessarily it should be the last one. Also if the jacket has only one button, it should be fastened, so the jacket will not swinging open.You are given a jacket with n buttons. Determine if it is fastened in a right way.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"843"Just to remind, girls in Arpa's land are really nice.Mehrdad wants to invite some Hoses to the palace for a dancing party. Each Hos has some weight wi and some beauty bi. Also each Hos may have some friends. Hoses are divided in some friendship groups. Two Hoses x and y are in the same friendship group if and only if there is a sequence of Hoses a1, a2, ..., ak such that ai and ai + 1 are friends for each 1 ≤ i < k, and a1 = x and ak = y.  Arpa allowed to use the amphitheater of palace to Mehrdad for this party. Arpa's amphitheater can hold at most w weight on it. Mehrdad is so greedy that he wants to invite some Hoses such that sum of their weights is not greater than w and sum of their beauties is as large as possible. Along with that, from each friendship group he can either invite all Hoses, or no more than one. Otherwise, some Hoses will be hurt. Find for Mehrdad the maximum possible total beauty of Hoses he can invite so that no one gets hurt and the total weight doesn't exceed w.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"844"You are given a permutation $$$p$$$ of $$$n$$$ integers $$$1$$$, $$$2$$$, ..., $$$n$$$ (a permutation is an array where each element from $$$1$$$ to $$$n$$$ occurs exactly once).Let's call some subsegment $$$p[l, r]$$$ of this permutation special if $$$p_l + p_r = \max \limits_{i = l}^{r} p_i$$$. Please calculate the number of special subsegments.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"845"An undirected graph is called k-regular, if the degrees of all its vertices are equal k. An edge of a connected graph is called a bridge, if after removing it the graph is being split into two connected components.Build a connected undirected k-regular graph containing at least one bridge, or else state that such graph doesn't exist.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"846"In the evenings Donkey would join Shrek to look at the stars. They would sit on a log, sipping tea and they would watch the starry sky. The sky hung above the roof, right behind the chimney. Shrek's stars were to the right of the chimney and the Donkey's stars were to the left. Most days the Donkey would just count the stars, so he knew that they are exactly n. This time he wanted a challenge. He imagined a coordinate system: he put the origin of the coordinates at the intersection of the roof and the chimney, directed the OX axis to the left along the roof and the OY axis — up along the chimney (see figure). The Donkey imagined two rays emanating from he origin of axes at angles α1 and α2 to the OX axis.  Now he chooses any star that lies strictly between these rays. After that he imagines more rays that emanate from this star at the same angles α1 and α2 to the OX axis and chooses another star that lies strictly between the new rays. He repeats the operation as long as there still are stars he can choose between the rays that emanate from a star.   As a result, the Donkey gets a chain of stars. He can consecutively get to each star if he acts by the given rules.Your task is to find the maximum number of stars m that the Donkey's chain can contain.Note that the chain must necessarily start in the point of the origin of the axes, that isn't taken into consideration while counting the number m of stars in the chain.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"847"It is the easy version of the problem. The only difference is that in this version $$$a_i \le 200$$$.You are given an array of $$$n$$$ integers $$$a_0, a_1, a_2, \ldots a_{n - 1}$$$. Bryap wants to find the longest beautiful subsequence in the array.An array $$$b = [b_0, b_1, \ldots, b_{m-1}]$$$, where $$$0 \le b_0 < b_1 < \ldots < b_{m - 1} < n$$$, is a subsequence of length $$$m$$$ of the array $$$a$$$.Subsequence $$$b = [b_0, b_1, \ldots, b_{m-1}]$$$ of length $$$m$$$ is called beautiful, if the following condition holds:   For any $$$p$$$ ($$$0 \le p < m - 1$$$) holds: $$$a_{b_p} \oplus b_{p+1} < a_{b_{p+1}} \oplus b_p$$$. Here $$$a \oplus b$$$ denotes the bitwise XOR of $$$a$$$ and $$$b$$$. For example, $$$2 \oplus 4 = 6$$$ and $$$3 \oplus 1=2$$$.Bryap is a simple person so he only wants to know the length of the longest such subsequence. Help Bryap and find the answer to his question.","['strings', 'trees']","[0, 0, 0, 0, 0, 0, 1, 1]"848"The problem describes the properties of a command line. The description somehow resembles the one you usually see in real operating systems. However, there are differences in the behavior. Please make sure you've read the statement attentively and use it as a formal document.In the Pindows operating system a strings are the lexemes of the command line — the first of them is understood as the name of the program to run and the following lexemes are its arguments. For example, as we execute the command "" run.exe one, two . "", we give four lexemes to the Pindows command line: ""run.exe"", ""one,"", ""two"", ""."". More formally, if we run a command that can be represented as string s (that has no quotes), then the command line lexemes are maximal by inclusion substrings of string s that contain no spaces.To send a string with spaces or an empty string as a command line lexeme, we can use double quotes. The block of characters that should be considered as one lexeme goes inside the quotes. Embedded quotes are prohibited — that is, for each occurrence of character """""" we should be able to say clearly that the quotes are opening or closing. For example, as we run the command """"run.exe o"" """" "" ne, "" two . "" "" "", we give six lexemes to the Pindows command line: ""run.exe o"", """" (an empty string), "" ne, "", ""two"", ""."", "" "" (a single space).It is guaranteed that each lexeme of the command line is either surrounded by spaces on both sides or touches the corresponding command border. One of its consequences is: the opening brackets are either the first character of the string or there is a space to the left of them.You have a string that consists of uppercase and lowercase English letters, digits, characters "".,?!"""" and spaces. It is guaranteed that this string is a correct OS Pindows command line string. Print all lexemes of this command line string. Consider the character """""" to be used only in order to denote a single block of characters into one command line lexeme. In particular, the consequence is that the given string has got an even number of such characters.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"849"Limak is a little polar bear. In the snow he found a scroll with the ancient prophecy. Limak doesn't know any ancient languages and thus is unable to understand the prophecy. But he knows digits!One fragment of the prophecy is a sequence of n digits. The first digit isn't zero. Limak thinks that it's a list of some special years. It's hard to see any commas or spaces, so maybe ancient people didn't use them. Now Limak wonders what years are listed there.Limak assumes three things:  Years are listed in the strictly increasing order;  Every year is a positive integer number;  There are no leading zeros. Limak is going to consider all possible ways to split a sequence into numbers (years), satisfying the conditions above. He will do it without any help. However, he asked you to tell him the number of ways to do so. Since this number may be very large, you are only asked to calculate it modulo 109 + 7.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"850"Vlad likes to eat in cafes very much. During his life, he has visited cafes n times. Unfortunately, Vlad started to feel that his last visits are not any different from each other. To fix that Vlad had a small research.First of all, Vlad assigned individual indices to all cafes. Then, he wrote down indices of cafes he visited in a row, in order of visiting them. Now, Vlad wants to find such a cafe that his last visit to that cafe was before his last visits to every other cafe. In other words, he wants to find such a cafe that he hasn't been there for as long as possible. Help Vlad to find that cafe.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"851"A bracketed sequence is called correct (regular) if by inserting ""+"" and ""1"" you can get a well-formed mathematical expression from it. For example, sequences ""(())()"", ""()"" and ""(()(()))"" are correct, while "")("", ""(()"" and ""(()))("" are not.The teacher gave Dmitry's class a very strange task — she asked every student to come up with a sequence of arbitrary length, consisting only of opening and closing brackets. After that all the students took turns naming the sequences they had invented. When Dima's turn came, he suddenly realized that all his classmates got the correct bracketed sequence, and whether he got the correct bracketed sequence, he did not know.Dima suspects now that he simply missed the word ""correct"" in the task statement, so now he wants to save the situation by modifying his sequence slightly. More precisely, he can the arbitrary number of times (possibly zero) perform the reorder operation.The reorder operation consists of choosing an arbitrary consecutive subsegment (substring) of the sequence and then reordering all the characters in it in an arbitrary way. Such operation takes $$$l$$$ nanoseconds, where $$$l$$$ is the length of the subsegment being reordered. It's easy to see that reorder operation doesn't change the number of opening and closing brackets. For example for ""))(("" he can choose the substring "")("" and do reorder "")()("" (this operation will take $$$2$$$ nanoseconds).Since Dima will soon have to answer, he wants to make his sequence correct as fast as possible. Help him to do this, or determine that it's impossible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"852"Polycarp has a checkered sheet of paper of size n × m. Polycarp painted some of cells with black, the others remained white. Inspired by Malevich's ""Black Square"", Polycarp wants to paint minimum possible number of white cells with black so that all black cells form a square.You are to determine the minimum possible number of cells needed to be painted black so that the black cells form a black square with sides parallel to the painting's sides. All the cells that do not belong to the square should be white. The square's side should have positive length.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"853"Lee is used to finish his stories in a stylish way, this time he barely failed it, but Ice Bear came and helped him. Lee is so grateful for it, so he decided to show Ice Bear his new game called ""Critic""...The game is a one versus one game. It has $$$t$$$ rounds, each round has two integers $$$s_i$$$ and $$$e_i$$$ (which are determined and are known before the game begins, $$$s_i$$$ and $$$e_i$$$ may differ from round to round). The integer $$$s_i$$$ is written on the board at the beginning of the corresponding round. The players will take turns. Each player will erase the number on the board (let's say it was $$$a$$$) and will choose to write either $$$2 \cdot a$$$ or $$$a + 1$$$ instead. Whoever writes a number strictly greater than $$$e_i$$$ loses that round and the other one wins that round.Now Lee wants to play ""Critic"" against Ice Bear, for each round he has chosen the round's $$$s_i$$$ and $$$e_i$$$ in advance. Lee will start the first round, the loser of each round will start the next round.The winner of the last round is the winner of the game, and the loser of the last round is the loser of the game.Determine if Lee can be the winner independent of Ice Bear's moves or not. Also, determine if Lee can be the loser independent of Ice Bear's moves or not.",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"854"You are given an integer $$$x$$$ of $$$n$$$ digits $$$a_1, a_2, \ldots, a_n$$$, which make up its decimal notation in order from left to right.Also, you are given a positive integer $$$k < n$$$.Let's call integer $$$b_1, b_2, \ldots, b_m$$$ beautiful if $$$b_i = b_{i+k}$$$ for each $$$i$$$, such that $$$1 \leq i \leq m - k$$$.You need to find the smallest beautiful integer $$$y$$$, such that $$$y \geq x$$$. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"855"On Children's Day, the child got a toy from Delayyy as a present. However, the child is so naughty that he can't wait to destroy the toy.The toy consists of n parts and m ropes. Each rope links two parts, but every pair of parts is linked by at most one rope. To split the toy, the child must remove all its parts. The child can remove a single part at a time, and each remove consume an energy. Let's define an energy value of part i as vi. The child spend vf1 + vf2 + ... + vfk energy for removing part i where f1, f2, ..., fk are the parts that are directly connected to the i-th and haven't been removed.Help the child to find out, what is the minimum total energy he should spend to remove all n parts.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"856"There is a square painted on a piece of paper, the square's side equals n meters. John Doe draws crosses on the square's perimeter. John paints the first cross in the lower left corner of the square. Then John moves along the square's perimeter in the clockwise direction (first upwards, then to the right, then downwards, then to the left and so on). Every time he walks (n + 1) meters, he draws a cross (see picture for clarifications).John Doe stops only when the lower left corner of the square has two crosses. How many crosses will John draw?   The figure shows the order in which John draws crosses for a square with side 4. The lower left square has two crosses. Overall John paints 17 crosses.  ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"857"Kevin Sun has just finished competing in Codeforces Round #334! The round was 120 minutes long and featured five problems with maximum point values of 500, 1000, 1500, 2000, and 2500, respectively. Despite the challenging tasks, Kevin was uncowed and bulldozed through all of them, distinguishing himself from the herd as the best cowmputer scientist in all of Bovinia. Kevin knows his submission time for each problem, the number of wrong submissions that he made on each problem, and his total numbers of successful and unsuccessful hacks. Because Codeforces scoring is complicated, Kevin wants you to write a program to compute his final score.Codeforces scores are computed as follows: If the maximum point value of a problem is x, and Kevin submitted correctly at minute m but made w wrong submissions, then his score on that problem is . His total score is equal to the sum of his scores for each problem. In addition, Kevin's total score gets increased by 100 points for each successful hack, but gets decreased by 50 points for each unsuccessful hack.All arithmetic operations are performed with absolute precision and no rounding. It is guaranteed that Kevin's final score is an integer.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"858"You received a notebook which is called Death Note. This notebook has infinite number of pages. A rule is written on the last page (huh) of this notebook. It says: ""You have to write names in this notebook during $$$n$$$ consecutive days. During the $$$i$$$-th day you have to write exactly $$$a_i$$$ names."". You got scared (of course you got scared, who wouldn't get scared if he just receive a notebook which is named Death Note with a some strange rule written in it?).Of course, you decided to follow this rule. When you calmed down, you came up with a strategy how you will write names in the notebook. You have calculated that each page of the notebook can contain exactly $$$m$$$ names. You will start writing names from the first page. You will write names on the current page as long as the limit on the number of names on this page is not exceeded. When the current page is over, you turn the page. Note that you always turn the page when it ends, it doesn't matter if it is the last day or not. If after some day the current page still can hold at least one name, during the next day you will continue writing the names from the current page.Now you are interested in the following question: how many times will you turn the page during each day? You are interested in the number of pages you will turn each day from $$$1$$$ to $$$n$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"859"There are two sisters Alice and Betty. You have $$$n$$$ candies. You want to distribute these $$$n$$$ candies between two sisters in such a way that:  Alice will get $$$a$$$ ($$$a > 0$$$) candies;  Betty will get $$$b$$$ ($$$b > 0$$$) candies;  each sister will get some integer number of candies;  Alice will get a greater amount of candies than Betty (i.e. $$$a > b$$$);  all the candies will be given to one of two sisters (i.e. $$$a+b=n$$$). Your task is to calculate the number of ways to distribute exactly $$$n$$$ candies between sisters in a way described above. Candies are indistinguishable.Formally, find the number of ways to represent $$$n$$$ as the sum of $$$n=a+b$$$, where $$$a$$$ and $$$b$$$ are positive integers and $$$a>b$$$.You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"860"You have two strings $$$a$$$ and $$$b$$$ of equal even length $$$n$$$ consisting of characters 0 and 1.We're in the endgame now. To finally make the universe perfectly balanced, you need to make strings $$$a$$$ and $$$b$$$ equal.In one step, you can choose any prefix of $$$a$$$ of even length and reverse it. Formally, if $$$a = a_1 a_2 \ldots a_n$$$, you can choose a positive even integer $$$p \le n$$$ and set $$$a$$$ to $$$a_p a_{p-1} \ldots a_1 a_{p+1} a_{p+2} \ldots a_n$$$.Find a way to make $$$a$$$ equal to $$$b$$$ using at most $$$n + 1$$$ reversals of the above kind, or determine that such a way doesn't exist. The number of reversals doesn't have to be minimized.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"861"Emuskald is a well-known illusionist. One of his trademark tricks involves a set of magical boxes. The essence of the trick is in packing the boxes inside other boxes.From the top view each magical box looks like a square with side length equal to 2k (k is an integer, k ≥ 0) units. A magical box v can be put inside a magical box u, if side length of v is strictly less than the side length of u. In particular, Emuskald can put 4 boxes of side length 2k - 1 into one box of side length 2k, or as in the following figure:  Emuskald is about to go on tour performing around the world, and needs to pack his magical boxes for the trip. He has decided that the best way to pack them would be inside another magical box, but magical boxes are quite expensive to make. Help him find the smallest magical box that can fit all his boxes.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"862"Dima has a birthday soon! It's a big day! Saryozha's present to Dima is that Seryozha won't be in the room and won't disturb Dima and Inna as they celebrate the birthday. Inna's present to Dima is a stack, a queue and a deck.Inna wants her present to show Dima how great a programmer he is. For that, she is going to give Dima commands one by one. There are two types of commands:  Add a given number into one of containers. For the queue and the stack, you can add elements only to the end. For the deck, you can add elements to the beginning and to the end.  Extract a number from each of at most three distinct containers. Tell all extracted numbers to Inna and then empty all containers. In the queue container you can extract numbers only from the beginning. In the stack container you can extract numbers only from the end. In the deck number you can extract numbers from the beginning and from the end. You cannot extract numbers from empty containers. Every time Dima makes a command of the second type, Inna kisses Dima some (possibly zero) number of times. Dima knows Inna perfectly well, he is sure that this number equals the sum of numbers he extracts from containers during this operation.As we've said before, Dima knows Inna perfectly well and he knows which commands Inna will give to Dima and the order of the commands. Help Dima find the strategy that lets him give as more kisses as possible for his birthday!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"863"Note that the only difference between String Transformation 1 and String Transformation 2 is in the move Koa does. In this version the letter $$$y$$$ Koa selects must be strictly greater alphabetically than $$$x$$$ (read statement for better understanding). You can make hacks in these problems independently.Koa the Koala has two strings $$$A$$$ and $$$B$$$ of the same length $$$n$$$ ($$$|A|=|B|=n$$$) consisting of the first $$$20$$$ lowercase English alphabet letters (ie. from a to t).In one move Koa:  selects some subset of positions $$$p_1, p_2, \ldots, p_k$$$ ($$$k \ge 1; 1 \le p_i \le n; p_i \neq p_j$$$ if $$$i \neq j$$$) of $$$A$$$ such that $$$A_{p_1} = A_{p_2} = \ldots = A_{p_k} = x$$$ (ie. all letters on this positions are equal to some letter $$$x$$$).  selects a letter $$$y$$$ (from the first $$$20$$$ lowercase letters in English alphabet) such that $$$y>x$$$ (ie. letter $$$y$$$ is strictly greater alphabetically than $$$x$$$).  sets each letter in positions $$$p_1, p_2, \ldots, p_k$$$ to letter $$$y$$$. More formally: for each $$$i$$$ ($$$1 \le i \le k$$$) Koa sets $$$A_{p_i} = y$$$. Note that you can only modify letters in string $$$A$$$.Koa wants to know the smallest number of moves she has to do to make strings equal to each other ($$$A = B$$$) or to determine that there is no way to make them equal. Help her!","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"864"There is one apple tree in Arkady's garden. It can be represented as a set of junctions connected with branches so that there is only one way to reach any junctions from any other one using branches. The junctions are enumerated from $$$1$$$ to $$$n$$$, the junction $$$1$$$ is called the root.A subtree of a junction $$$v$$$ is a set of junctions $$$u$$$ such that the path from $$$u$$$ to the root must pass through $$$v$$$. Note that $$$v$$$ itself is included in a subtree of $$$v$$$.A leaf is such a junction that its subtree contains exactly one junction.The New Year is coming, so Arkady wants to decorate the tree. He will put a light bulb of some color on each leaf junction and then count the number happy junctions. A happy junction is such a junction $$$t$$$ that all light bulbs in the subtree of $$$t$$$ have different colors.Arkady is interested in the following question: for each $$$k$$$ from $$$1$$$ to $$$n$$$, what is the minimum number of different colors needed to make the number of happy junctions be greater than or equal to $$$k$$$?","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"865"Berland scientists face a very important task - given the parts of short DNA fragments, restore the dinosaur DNA! The genome of a berland dinosaur has noting in common with the genome that we've used to: it can have 26 distinct nucleotide types, a nucleotide of each type can occur at most once. If we assign distinct English letters to all nucleotides, then the genome of a Berland dinosaur will represent a non-empty string consisting of small English letters, such that each letter occurs in it at most once.Scientists have n genome fragments that are represented as substrings (non-empty sequences of consecutive nucleotides) of the sought genome.You face the following problem: help scientists restore the dinosaur genome. It is guaranteed that the input is not contradictory and at least one suitable line always exists. When the scientists found out that you are a strong programmer, they asked you in addition to choose the one with the minimum length. If there are multiple such strings, choose any string.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"866"Alice became interested in periods of integer numbers. We say positive $$$X$$$ integer number is periodic with length $$$L$$$ if there exists positive integer number $$$P$$$ with $$$L$$$ digits such that $$$X$$$ can be written as $$$PPPP…P$$$. For example:$$$X = 123123123$$$ is periodic number with length $$$L = 3$$$ and $$$L = 9$$$$$$X = 42424242$$$ is periodic number with length $$$L = 2,L = 4$$$ and $$$L = 8$$$$$$X = 12345$$$ is periodic number with length $$$L = 5$$$For given positive period length $$$L$$$ and positive integer number $$$A$$$, Alice wants to find smallest integer number $$$X$$$ strictly greater than $$$A$$$ that is periodic with length L.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"867"Let's define the value of the permutation $$$p$$$ of $$$n$$$ integers $$$1$$$, $$$2$$$, ..., $$$n$$$ (a permutation is an array where each element from $$$1$$$ to $$$n$$$ occurs exactly once) as follows:  initially, an integer variable $$$x$$$ is equal to $$$0$$$;  if $$$x < p_1$$$, then add $$$p_1$$$ to $$$x$$$ (set $$$x = x + p_1$$$), otherwise assign $$$0$$$ to $$$x$$$;  if $$$x < p_2$$$, then add $$$p_2$$$ to $$$x$$$ (set $$$x = x + p_2$$$), otherwise assign $$$0$$$ to $$$x$$$;  ...  if $$$x < p_n$$$, then add $$$p_n$$$ to $$$x$$$ (set $$$x = x + p_n$$$), otherwise assign $$$0$$$ to $$$x$$$;  the value of the permutation is $$$x$$$ at the end of this process. For example, for $$$p = [4, 5, 1, 2, 3, 6]$$$, the value of $$$x$$$ changes as follows: $$$0, 4, 9, 0, 2, 5, 11$$$, so the value of the permutation is $$$11$$$.You are given an integer $$$n$$$. Find a permutation $$$p$$$ of size $$$n$$$ with the maximum possible value among all permutations of size $$$n$$$. If there are several such permutations, you can print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"868"You are given an array of n integer numbers a0, a1, ..., an - 1. Find the distance between two closest (nearest) minimums in it. It is guaranteed that in the array a minimum occurs at least two times.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"869"Oleg the bank client and Igor the analyst are arguing again. This time, they want to pick a gift as a present for their friend, ZS the coder. After a long thought, they decided that their friend loves to eat carrots the most and thus they want to pick the best carrot as their present.There are n carrots arranged in a line. The i-th carrot from the left has juiciness ai. Oleg thinks ZS loves juicy carrots whereas Igor thinks that he hates juicy carrots. Thus, Oleg would like to maximize the juiciness of the carrot they choose while Igor would like to minimize the juiciness of the carrot they choose.To settle this issue, they decided to play a game again. Oleg and Igor take turns to play the game. In each turn, a player can choose a carrot from either end of the line, and eat it. The game ends when only one carrot remains. Oleg moves first. The last remaining carrot will be the carrot that they will give their friend, ZS.Oleg is a sneaky bank client. When Igor goes to a restroom, he performs k moves before the start of the game. Each move is the same as above (eat a carrot from either end of the line). After Igor returns, they start the game with Oleg still going first. Oleg wonders: for each k such that 0 ≤ k ≤ n - 1, what is the juiciness of the carrot they will give to ZS if he makes k extra moves beforehand and both players play optimally?","['games', 'math']","[1, 0, 0, 1, 0, 0, 0, 0]"870"You are given a sequence of $$$n$$$ pairs of integers: $$$(a_1, b_1), (a_2, b_2), \dots , (a_n, b_n)$$$. This sequence is called bad if it is sorted in non-descending order by first elements or if it is sorted in non-descending order by second elements. Otherwise the sequence is good. There are examples of good and bad sequences:  $$$s = [(1, 2), (3, 2), (3, 1)]$$$ is bad because the sequence of first elements is sorted: $$$[1, 3, 3]$$$;  $$$s = [(1, 2), (3, 2), (1, 2)]$$$ is bad because the sequence of second elements is sorted: $$$[2, 2, 2]$$$;  $$$s = [(1, 1), (2, 2), (3, 3)]$$$ is bad because both sequences (the sequence of first elements and the sequence of second elements) are sorted;  $$$s = [(1, 3), (3, 3), (2, 2)]$$$ is good because neither the sequence of first elements $$$([1, 3, 2])$$$ nor the sequence of second elements $$$([3, 3, 2])$$$ is sorted. Calculate the number of permutations of size $$$n$$$ such that after applying this permutation to the sequence $$$s$$$ it turns into a good sequence. A permutation $$$p$$$ of size $$$n$$$ is a sequence $$$p_1, p_2, \dots , p_n$$$ consisting of $$$n$$$ distinct integers from $$$1$$$ to $$$n$$$ ($$$1 \le p_i \le n$$$). If you apply permutation $$$p_1, p_2, \dots , p_n$$$ to the sequence $$$s_1, s_2, \dots , s_n$$$ you get the sequence $$$s_{p_1}, s_{p_2}, \dots , s_{p_n}$$$. For example, if $$$s = [(1, 2), (1, 3), (2, 3)]$$$ and $$$p = [2, 3, 1]$$$ then $$$s$$$ turns into $$$[(1, 3), (2, 3), (1, 2)]$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"871"On a chessboard with a width of $$$10^9$$$ and a height of $$$10^9$$$, the rows are numbered from bottom to top from $$$1$$$ to $$$10^9$$$, and the columns are numbered from left to right from $$$1$$$ to $$$10^9$$$. Therefore, for each cell of the chessboard you can assign the coordinates $$$(x,y)$$$, where $$$x$$$ is the column number and $$$y$$$ is the row number.Every day there are fights between black and white pieces on this board. Today, the black ones won, but at what price? Only the rook survived, and it was driven into the lower left corner — a cell with coordinates $$$(1,1)$$$. But it is still happy, because the victory has been won and it's time to celebrate it! In order to do this, the rook needs to go home, namely — on the upper side of the field (that is, in any cell that is in the row with number $$$10^9$$$).Everything would have been fine, but the treacherous white figures put spells on some places of the field before the end of the game. There are two types of spells:   Vertical. Each of these is defined by one number $$$x$$$. Such spells create an infinite blocking line between the columns $$$x$$$ and $$$x+1$$$.  Horizontal. Each of these is defined by three numbers $$$x_1$$$, $$$x_2$$$, $$$y$$$. Such spells create a blocking segment that passes through the top side of the cells, which are in the row $$$y$$$ and in columns from $$$x_1$$$ to $$$x_2$$$ inclusive. The peculiarity of these spells is that it is impossible for a certain pair of such spells to have a common point. Note that horizontal spells can have common points with vertical spells.    An example of a chessboard. Let's recall that the rook is a chess piece that in one move can move to any point that is in the same row or column with its initial position. In our task, the rook can move from the cell $$$(r_0,c_0)$$$ into the cell $$$(r_1,c_1)$$$ only under the condition that $$$r_1 = r_0$$$ or $$$c_1 = c_0$$$ and there is no blocking lines or blocking segments between these cells (For better understanding, look at the samples).Fortunately, the rook can remove spells, but for this it has to put tremendous efforts, therefore, it wants to remove the minimum possible number of spells in such way, that after this it can return home. Find this number!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"872"You are given an array $$$a$$$ of length $$$n$$$. The array is called 3SUM-closed if for all distinct indices $$$i$$$, $$$j$$$, $$$k$$$, the sum $$$a_i + a_j + a_k$$$ is an element of the array. More formally, $$$a$$$ is 3SUM-closed if for all integers $$$1 \leq i < j < k \leq n$$$, there exists some integer $$$1 \leq l \leq n$$$ such that $$$a_i + a_j + a_k = a_l$$$.Determine if $$$a$$$ is 3SUM-closed.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"873"A positive integer $$$x$$$ is called a power of two if it can be represented as $$$x = 2^y$$$, where $$$y$$$ is a non-negative integer. So, the powers of two are $$$1, 2, 4, 8, 16, \dots$$$.You are given two positive integers $$$n$$$ and $$$k$$$. Your task is to represent $$$n$$$ as the sum of exactly $$$k$$$ powers of two.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"874"Overall there are m actors in Berland. Each actor has a personal identifier — an integer from 1 to m (distinct actors have distinct identifiers). Vasya likes to watch Berland movies with Berland actors, and he has k favorite actors. He watched the movie trailers for the next month and wrote the following information for every movie: the movie title, the number of actors who starred in it, and the identifiers of these actors. Besides, he managed to copy the movie titles and how many actors starred there, but he didn't manage to write down the identifiers of some actors. Vasya looks at his records and wonders which movies may be his favourite, and which ones may not be. Once Vasya learns the exact cast of all movies, his favorite movies will be determined as follows: a movie becomes favorite movie, if no other movie from Vasya's list has more favorite actors.Help the boy to determine the following for each movie: whether it surely will be his favourite movie; whether it surely won't be his favourite movie;  can either be favourite or not.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"875"You are given $$$n$$$ lengths of segments that need to be placed on an infinite axis with coordinates.The first segment is placed on the axis so that one of its endpoints lies at the point with coordinate $$$0$$$. Let's call this endpoint the ""start"" of the first segment and let's call its ""end"" as that endpoint that is not the start. The ""start"" of each following segment must coincide with the ""end"" of the previous one. Thus, if the length of the next segment is $$$d$$$ and the ""end"" of the previous one has the coordinate $$$x$$$, the segment can be placed either on the coordinates $$$[x-d, x]$$$, and then the coordinate of its ""end"" is $$$x - d$$$, or on the coordinates $$$[x, x+d]$$$, in which case its ""end"" coordinate is $$$x + d$$$.The total coverage of the axis by these segments is defined as their overall union which is basically the set of points covered by at least one of the segments. It's easy to show that the coverage will also be a segment on the axis. Determine the minimal possible length of the coverage that can be obtained by placing all the segments on the axis without changing their order.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"876You are given an array $$$a$$$ consisting of $$$n$$$ positive integers. Find a non-empty subset of its elements such that their sum is even (i.e. divisible by $$$2$$$) or determine that there is no such subset.Both the given array and required subset may contain equal values.,[],"[0, 0, 0, 0, 0, 0, 0, 0]"877"This version of the problem differs from the previous one only in the constraint on $$$n$$$.A tree is a connected undirected graph without cycles. A weighted tree has a weight assigned to each edge. The distance between two vertices is the minimum sum of weights on the path connecting them.You are given a weighted tree with $$$n$$$ vertices, each edge has a weight of $$$1$$$. Denote $$$d(v)$$$ as the distance between vertex $$$1$$$ and vertex $$$v$$$.Let $$$f(x)$$$ be the minimum possible value of $$$\max\limits_{1 \leq v \leq n} \ {d(v)}$$$ if you can temporarily add an edge with weight $$$x$$$ between any two vertices $$$a$$$ and $$$b$$$ $$$(1 \le a, b \le n)$$$. Note that after this operation, the graph is no longer a tree.For each integer $$$x$$$ from $$$1$$$ to $$$n$$$, find $$$f(x)$$$.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"878"User ainta loves to play with cards. He has a cards containing letter ""o"" and b cards containing letter ""x"". He arranges the cards in a row, and calculates the score of the deck by the formula below.  At first, the score is 0.  For each block of contiguous ""o""s with length x the score increases by x2.  For each block of contiguous ""x""s with length y the score decreases by y2.   For example, if a = 6, b = 3 and ainta have arranged the cards in the order, that is described by string ""ooxoooxxo"", the score of the deck equals 22 - 12 + 32 - 22 + 12 = 9. That is because the deck has 5 blocks in total: ""oo"", ""x"", ""ooo"", ""xx"", ""o"".User ainta likes big numbers, so he wants to maximize the score with the given cards. Help ainta make the score as big as possible. Note, that he has to arrange all his cards.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"879"Some people leave the lights at their workplaces on when they leave that is a waste of resources. As a hausmeister of DHBW, Sagheer waits till all students and professors leave the university building, then goes and turns all the lights off.The building consists of n floors with stairs at the left and the right sides. Each floor has m rooms on the same line with a corridor that connects the left and right stairs passing by all the rooms. In other words, the building can be represented as a rectangle with n rows and m + 2 columns, where the first and the last columns represent the stairs, and the m columns in the middle represent rooms.Sagheer is standing at the ground floor at the left stairs. He wants to turn all the lights off in such a way that he will not go upstairs until all lights in the floor he is standing at are off. Of course, Sagheer must visit a room to turn the light there off. It takes one minute for Sagheer to go to the next floor using stairs or to move from the current room/stairs to a neighboring room/stairs on the same floor. It takes no time for him to switch the light off in the room he is currently standing in. Help Sagheer find the minimum total time to turn off all the lights.Note that Sagheer does not have to go back to his starting position, and he does not have to visit rooms where the light is already switched off.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"880"You are given $$$n$$$ strings $$$s_1, s_2, \dots, s_n$$$ of length at most $$$\mathbf{8}$$$. For each string $$$s_i$$$, determine if there exist two strings $$$s_j$$$ and $$$s_k$$$ such that $$$s_i = s_j + s_k$$$. That is, $$$s_i$$$ is the concatenation of $$$s_j$$$ and $$$s_k$$$. Note that $$$j$$$ can be equal to $$$k$$$.Recall that the concatenation of strings $$$s$$$ and $$$t$$$ is $$$s + t = s_1 s_2 \dots s_p t_1 t_2 \dots t_q$$$, where $$$p$$$ and $$$q$$$ are the lengths of strings $$$s$$$ and $$$t$$$ respectively. For example, concatenation of ""code"" and ""forces"" is ""codeforces"".",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"881"This is an interactive problem.A legendary tree rests deep in the forest. Legend has it that individuals who realize this tree would eternally become a Legendary Grandmaster.To help you determine the tree, Mikaela the Goddess has revealed to you that the tree contains $$$n$$$ vertices, enumerated from $$$1$$$ through $$$n$$$. She also allows you to ask her some questions as follows. For each question, you should tell Mikaela some two disjoint non-empty sets of vertices $$$S$$$ and $$$T$$$, along with any vertex $$$v$$$ that you like. Then, Mikaela will count and give you the number of pairs of vertices $$$(s, t)$$$ where $$$s \in S$$$ and $$$t \in T$$$ such that the simple path from $$$s$$$ to $$$t$$$ contains $$$v$$$.Mikaela the Goddess is busy and will be available to answer at most $$$11\,111$$$ questions.This is your only chance. Your task is to determine the tree and report its edges.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"882You are given two integer arrays $$$a$$$ and $$$b$$$ of length $$$n$$$.You can reverse at most one subarray (continuous subsegment) of the array $$$a$$$. Your task is to reverse such a subarray that the sum $$$\sum\limits_{i=1}^n a_i \cdot b_i$$$ is maximized.,['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"883"Fibonacci strings are defined as follows:   f1 = «a»  f2 = «b»  fn = fn - 1 fn - 2, n > 2 Thus, the first five Fibonacci strings are: ""a"", ""b"", ""ba"", ""bab"", ""babba"".You are given a Fibonacci string and m strings si. For each string si, find the number of times it occurs in the given Fibonacci string as a substring.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"884"$$$n$$$ people gathered to hold a jury meeting of the upcoming competition, the $$$i$$$-th member of the jury came up with $$$a_i$$$ tasks, which they want to share with each other.First, the jury decides on the order which they will follow while describing the tasks. Let that be a permutation $$$p$$$ of numbers from $$$1$$$ to $$$n$$$ (an array of size $$$n$$$ where each integer from $$$1$$$ to $$$n$$$ occurs exactly once).Then the discussion goes as follows:  If a jury member $$$p_1$$$ has some tasks left to tell, then they tell one task to others. Otherwise, they are skipped.  If a jury member $$$p_2$$$ has some tasks left to tell, then they tell one task to others. Otherwise, they are skipped.  ...  If a jury member $$$p_n$$$ has some tasks left to tell, then they tell one task to others. Otherwise, they are skipped.  If there are still members with tasks left, then the process repeats from the start. Otherwise, the discussion ends. A permutation $$$p$$$ is nice if none of the jury members tell two or more of their own tasks in a row. Count the number of nice permutations. The answer may be really large, so print it modulo $$$998\,244\,353$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"885"Ori and Sein have overcome many difficult challenges. They finally lit the Shrouded Lantern and found Gumon Seal, the key to the Forlorn Ruins. When they tried to open the door to the ruins... nothing happened.Ori was very surprised, but Sein gave the explanation quickly: clever Gumon decided to make an additional defence for the door.There are $$$n$$$ lamps with Spirit Tree's light. Sein knows the time of turning on and off for the $$$i$$$-th lamp — $$$l_i$$$ and $$$r_i$$$ respectively. To open the door you have to choose $$$k$$$ lamps in such a way that there will be a moment of time when they all will be turned on.While Sein decides which of the $$$k$$$ lamps to pick, Ori is interested: how many ways there are to pick such $$$k$$$ lamps that the door will open? It may happen that Sein may be wrong and there are no such $$$k$$$ lamps. The answer might be large, so print it modulo $$$998\,244\,353$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"886"Everool has a binary string $$$s$$$ of length $$$2n$$$. Note that a binary string is a string consisting of only characters $$$0$$$ and $$$1$$$. He wants to partition $$$s$$$ into two disjoint equal subsequences. He needs your help to do it.You are allowed to do the following operation exactly once.   You can choose any subsequence (possibly empty) of $$$s$$$ and rotate it right by one position. In other words, you can select a sequence of indices $$$b_1, b_2, \ldots, b_m$$$, where $$$1 \le b_1 < b_2 < \ldots < b_m \le 2n$$$. After that you simultaneously set $$$$$$s_{b_1} := s_{b_m},$$$$$$ $$$$$$s_{b_2} := s_{b_1},$$$$$$ $$$$$$\ldots,$$$$$$ $$$$$$s_{b_m} := s_{b_{m-1}}.$$$$$$Can you partition $$$s$$$ into two disjoint equal subsequences after performing the allowed operation exactly once?A partition of $$$s$$$ into two disjoint equal subsequences $$$s^p$$$ and $$$s^q$$$ is two increasing arrays of indices $$$p_1, p_2, \ldots, p_n$$$ and $$$q_1, q_2, \ldots, q_n$$$, such that each integer from $$$1$$$ to $$$2n$$$ is encountered in either $$$p$$$ or $$$q$$$ exactly once, $$$s^p = s_{p_1} s_{p_2} \ldots s_{p_n}$$$, $$$s^q = s_{q_1} s_{q_2} \ldots s_{q_n}$$$, and $$$s^p = s^q$$$.If it is not possible to partition after performing any kind of operation, report $$$-1$$$. If it is possible to do the operation and partition $$$s$$$ into two disjoint subsequences $$$s^p$$$ and $$$s^q$$$, such that $$$s^p = s^q$$$, print elements of $$$b$$$ and indices of $$$s^p$$$, i. e. the values $$$p_1, p_2, \ldots, p_n$$$.","['geometry', 'strings']","[0, 1, 0, 0, 0, 0, 1, 0]"887"All our characters have hobbies. The same is true for Fedor. He enjoys shopping in the neighboring supermarket. The goods in the supermarket have unique integer ids. Also, for every integer there is a product with id equal to this integer. Fedor has n discount coupons, the i-th of them can be used with products with ids ranging from li to ri, inclusive. Today Fedor wants to take exactly k coupons with him.Fedor wants to choose the k coupons in such a way that the number of such products x that all coupons can be used with this product x is as large as possible (for better understanding, see examples). Fedor wants to save his time as well, so he asks you to choose coupons for him. Help Fedor!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"888"We are sum for we are manySome NumberThis version of the problem differs from the previous one only in the constraint on $$$t$$$. You can make hacks only if both versions of the problem are solved.You are given two positive integers $$$l$$$ and $$$r$$$.Count the number of distinct triplets of integers $$$(i, j, k)$$$ such that $$$l \le i < j < k \le r$$$ and $$$\operatorname{lcm}(i,j,k) \ge i + j + k$$$.Here $$$\operatorname{lcm}(i, j, k)$$$ denotes the least common multiple (LCM) of integers $$$i$$$, $$$j$$$, and $$$k$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"889"You are given a sequence of n integers a1, a2, ..., an. Determine a real number x such that the weakness of the sequence a1 - x, a2 - x, ..., an - x is as small as possible.The weakness of a sequence is defined as the maximum value of the poorness over all segments (contiguous subsequences) of a sequence.The poorness of a segment is defined as the absolute value of sum of the elements of segment.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"890"Polycarp has found a table having an infinite number of rows and columns. The rows are numbered from $$$1$$$, starting from the topmost one. The columns are numbered from $$$1$$$, starting from the leftmost one.Initially, the table hasn't been filled and Polycarp wants to fix it. He writes integers from $$$1$$$ and so on to the table as follows.  The figure shows the placement of the numbers from $$$1$$$ to $$$10$$$. The following actions are denoted by the arrows. The leftmost topmost cell of the table is filled with the number $$$1$$$. Then he writes in the table all positive integers beginning from $$$2$$$ sequentially using the following algorithm.First, Polycarp selects the leftmost non-filled cell in the first row and fills it. Then, while the left neighbor of the last filled cell is filled, he goes down and fills the next cell. So he goes down until the last filled cell has a non-filled neighbor to the left (look at the vertical arrow going down in the figure above).After that, he fills the cells from the right to the left until he stops at the first column (look at the horizontal row in the figure above). Then Polycarp selects the leftmost non-filled cell in the first row, goes down, and so on.A friend of Polycarp has a favorite number $$$k$$$. He wants to know which cell will contain the number. Help him to find the indices of the row and the column, such that the intersection of the row and the column is the cell containing the number $$$k$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"891"Andrey's favourite number is n. Andrey's friends gave him two identical numbers n as a New Year present. He hung them on a wall and watched them adoringly.Then Andrey got bored from looking at the same number and he started to swap digits first in one, then in the other number, then again in the first number and so on (arbitrary number of changes could be made in each number). At some point it turned out that if we sum the resulting numbers, then the number of zeroes with which the sum will end would be maximum among the possible variants of digit permutations in those numbers.Given number n, can you find the two digit permutations that have this property?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"892"Having bought his own apartment, Boris decided to paper the walls in every room. Boris's flat has n rooms, each of which has the form of a rectangular parallelepiped. For every room we known its length, width and height of the walls in meters (different rooms can have different dimensions, including height).Boris chose m types of wallpaper to paper the walls of the rooms with (but it is not necessary to use all the types). Each type of wallpaper is sold in rolls of a fixed length and width (the length, naturally, shows how long the unfolded roll will be). In addition, for each type we know the price of one roll of this type.The wallpaper of each type contains strips running along the length of the roll. When gluing the strips must be located strictly vertically (so the roll cannot be rotated, even if the length is less than the width). Besides, a roll can be cut in an arbitrary manner, but the joints of glued pieces should also be vertical. In addition, each room should be papered by only one type of wallpaper. And pieces of the same roll cannot be used to paper different rooms. That is, for each room the rolls are purchased separately. Also, some rolls can be used not completely.After buying an apartment Boris is short of cash, so he wants to spend the minimum money on wallpaper. Help him.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"893"This is the easy version of the problem. The only difference is that in this version $$$q = 1$$$.You are given an array of integers $$$a_1, a_2, \ldots, a_n$$$.The cost of a subsegment of the array $$$[l, r]$$$, $$$1 \leq l \leq r \leq n$$$, is the value $$$f(l, r) = \operatorname{sum}(l, r) - \operatorname{xor}(l, r)$$$, where $$$\operatorname{sum}(l, r) = a_l + a_{l+1} + \ldots + a_r$$$, and $$$\operatorname{xor}(l, r) = a_l \oplus a_{l+1} \oplus \ldots \oplus a_r$$$ ($$$\oplus$$$ stands for bitwise XOR).You will have $$$q = 1$$$ query. Each query is given by a pair of numbers $$$L_i$$$, $$$R_i$$$, where $$$1 \leq L_i \leq R_i \leq n$$$. You need to find the subsegment $$$[l, r]$$$, $$$L_i \leq l \leq r \leq R_i$$$, with maximum value $$$f(l, r)$$$. If there are several answers, then among them you need to find a subsegment with the minimum length, that is, the minimum value of $$$r - l + 1$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"894"Omkar is playing his favorite pixelated video game, Bed Wars! In Bed Wars, there are $$$n$$$ players arranged in a circle, so that for all $$$j$$$ such that $$$2 \leq j \leq n$$$, player $$$j - 1$$$ is to the left of the player $$$j$$$, and player $$$j$$$ is to the right of player $$$j - 1$$$. Additionally, player $$$n$$$ is to the left of player $$$1$$$, and player $$$1$$$ is to the right of player $$$n$$$.Currently, each player is attacking either the player to their left or the player to their right. This means that each player is currently being attacked by either $$$0$$$, $$$1$$$, or $$$2$$$ other players. A key element of Bed Wars strategy is that if a player is being attacked by exactly $$$1$$$ other player, then they should logically attack that player in response. If instead a player is being attacked by $$$0$$$ or $$$2$$$ other players, then Bed Wars strategy says that the player can logically attack either of the adjacent players.Unfortunately, it might be that some players in this game are not following Bed Wars strategy correctly. Omkar is aware of whom each player is currently attacking, and he can talk to any amount of the $$$n$$$ players in the game to make them instead attack another player  — i. e. if they are currently attacking the player to their left, Omkar can convince them to instead attack the player to their right; if they are currently attacking the player to their right, Omkar can convince them to instead attack the player to their left. Omkar would like all players to be acting logically. Calculate the minimum amount of players that Omkar needs to talk to so that after all players he talked to (if any) have changed which player they are attacking, all players are acting logically according to Bed Wars strategy.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"895"You work as a system administrator in a dormitory, which has $$$n$$$ rooms one after another along a straight hallway. Rooms are numbered from $$$1$$$ to $$$n$$$.You have to connect all $$$n$$$ rooms to the Internet.You can connect each room to the Internet directly, the cost of such connection for the $$$i$$$-th room is $$$i$$$ coins. Some rooms also have a spot for a router. The cost of placing a router in the $$$i$$$-th room is also $$$i$$$ coins. You cannot place a router in a room which does not have a spot for it. When you place a router in the room $$$i$$$, you connect all rooms with the numbers from $$$max(1,~i - k)$$$ to $$$min(n,~i + k)$$$ inclusive to the Internet, where $$$k$$$ is the range of router. The value of $$$k$$$ is the same for all routers. Calculate the minimum total cost of connecting all $$$n$$$ rooms to the Internet. You can assume that the number of rooms which have a spot for a router is not greater than the number of routers you have.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"896"Long story short, shashlik is Miroslav's favorite food. Shashlik is prepared on several skewers simultaneously. There are two states for each skewer: initial and turned over.This time Miroslav laid out $$$n$$$ skewers parallel to each other, and enumerated them with consecutive integers from $$$1$$$ to $$$n$$$ in order from left to right. For better cooking, he puts them quite close to each other, so when he turns skewer number $$$i$$$, it leads to turning $$$k$$$ closest skewers from each side of the skewer $$$i$$$, that is, skewers number $$$i - k$$$, $$$i - k + 1$$$, ..., $$$i - 1$$$, $$$i + 1$$$, ..., $$$i + k - 1$$$, $$$i + k$$$ (if they exist). For example, let $$$n = 6$$$ and $$$k = 1$$$. When Miroslav turns skewer number $$$3$$$, then skewers with numbers $$$2$$$, $$$3$$$, and $$$4$$$ will come up turned over. If after that he turns skewer number $$$1$$$, then skewers number $$$1$$$, $$$3$$$, and $$$4$$$ will be turned over, while skewer number $$$2$$$ will be in the initial position (because it is turned again).As we said before, the art of cooking requires perfect timing, so Miroslav wants to turn over all $$$n$$$ skewers with the minimal possible number of actions. For example, for the above example $$$n = 6$$$ and $$$k = 1$$$, two turnings are sufficient: he can turn over skewers number $$$2$$$ and $$$5$$$.Help Miroslav turn over all $$$n$$$ skewers.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"897"Carl has $$$n$$$ coins of various colors, and he would like to sort them into piles. The coins are labeled $$$1,2,\ldots,n$$$, and each coin is exactly one of red, green, or blue. He would like to sort the coins into three different piles so one pile contains all red coins, one pile contains all green coins, and one pile contains all blue coins.Unfortunately, Carl is colorblind, so this task is impossible for him. Luckily, he has a friend who can take a pair of coins and tell Carl if they are the same color or not. Using his friend, Carl believes he can now sort the coins. The order of the piles doesn't matter, as long as all same colored coins are in the one pile, and no two different colored coins are in the same pile.His friend will answer questions about multiple pairs of coins in batches, and will answer about all of those pairs in parallel. Each coin should be in at most one pair in each batch. The same coin can appear in different batches.Carl can use only $$$7$$$ batches. Help him find the piles of coins after sorting.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"898"The Little Elephant loves playing with arrays. He has array a, consisting of n positive integers, indexed from 1 to n. Let's denote the number with index i as ai. Additionally the Little Elephant has m queries to the array, each query is characterised by a pair of integers lj and rj (1 ≤ lj ≤ rj ≤ n). For each query lj, rj the Little Elephant has to count, how many numbers x exist, such that number x occurs exactly x times among numbers alj, alj + 1, ..., arj.Help the Little Elephant to count the answers to all queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"899"Omkar is building a waterslide in his water park, and he needs your help to ensure that he does it as efficiently as possible.Omkar currently has $$$n$$$ supports arranged in a line, the $$$i$$$-th of which has height $$$a_i$$$. Omkar wants to build his waterslide from the right to the left, so his supports must be nondecreasing in height in order to support the waterslide. In $$$1$$$ operation, Omkar can do the following: take any contiguous subsegment of supports which is nondecreasing by heights and add $$$1$$$ to each of their heights. Help Omkar find the minimum number of operations he needs to perform to make his supports able to support his waterslide!An array $$$b$$$ is a subsegment of an array $$$c$$$ if $$$b$$$ can be obtained from $$$c$$$ by deletion of several (possibly zero or all) elements from the beginning and several (possibly zero or all) elements from the end.An array $$$b_1, b_2, \dots, b_n$$$ is called nondecreasing if $$$b_i\le b_{i+1}$$$ for every $$$i$$$ from $$$1$$$ to $$$n-1$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"900"Molly Hooper has n different kinds of chemicals arranged in a line. Each of the chemicals has an affection value, The i-th of them has affection value ai.Molly wants Sherlock to fall in love with her. She intends to do this by mixing a contiguous segment of chemicals together to make a love potion with total affection value as a non-negative integer power of k. Total affection value of a continuous segment of chemicals is the sum of affection values of each chemical in that segment.Help her to do so in finding the total number of such segments.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"901"Petya loves lucky numbers. We all know that lucky numbers are the positive integers whose decimal representations contain only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.Petya and his friend Vasya play an interesting game. Petya randomly chooses an integer p from the interval [pl, pr] and Vasya chooses an integer v from the interval [vl, vr] (also randomly). Both players choose their integers equiprobably. Find the probability that the interval [min(v, p), max(v, p)] contains exactly k lucky numbers.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"902"Gianni, SWERC's chief judge, received a huge amount of high quality problems from the judges and now he has to choose a problem set for SWERC.He received $$$n$$$ problems and he assigned a beauty score and a difficulty to each of them. The $$$i$$$-th problem has beauty score equal to $$$b_i$$$ and difficulty equal to $$$d_i$$$. The beauty and the difficulty are integers between $$$1$$$ and $$$10$$$. If there are no problems with a certain difficulty (the possible difficulties are $$$1,2,\dots,10$$$) then Gianni will ask for more problems to the judges.Otherwise, for each difficulty between $$$1$$$ and $$$10$$$, he will put in the problem set one of the most beautiful problems with such difficulty (so the problem set will contain exactly $$$10$$$ problems with distinct difficulties). You shall compute the total beauty of the problem set, that is the sum of the beauty scores of the problems chosen by Gianni.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"903"Alice had a permutation $$$p$$$ of numbers from $$$1$$$ to $$$n$$$. Alice can swap a pair $$$(x, y)$$$ which means swapping elements at positions $$$x$$$ and $$$y$$$ in $$$p$$$ (i.e. swap $$$p_x$$$ and $$$p_y$$$). Alice recently learned her first sorting algorithm, so she decided to sort her permutation in the minimum number of swaps possible. She wrote down all the swaps in the order in which she performed them to sort the permutation on a piece of paper. For example,  $$$[(2, 3), (1, 3)]$$$ is a valid swap sequence by Alice for permutation $$$p = [3, 1, 2]$$$ whereas $$$[(1, 3), (2, 3)]$$$ is not because it doesn't sort the permutation. Note that we cannot sort the permutation in less than $$$2$$$ swaps.  $$$[(1, 2), (2, 3), (2, 4), (2, 3)]$$$ cannot be a sequence of swaps by Alice for $$$p = [2, 1, 4, 3]$$$ even if it sorts the permutation because $$$p$$$ can be sorted in $$$2$$$ swaps, for example using the sequence $$$[(4, 3), (1, 2)]$$$. Unfortunately, Bob shuffled the sequence of swaps written by Alice.You are given Alice's permutation $$$p$$$ and the swaps performed by Alice in arbitrary order. Can you restore the correct sequence of swaps that sorts the permutation $$$p$$$? Since Alice wrote correct swaps before Bob shuffled them up, it is guaranteed that there exists some order of swaps that sorts the permutation.","['graphs', 'math', 'trees']","[0, 0, 1, 1, 0, 0, 0, 1]"904"It's well known that the best way to distract from something is to do one's favourite thing. Job is such a thing for Leha.So the hacker began to work hard in order to get rid of boredom. It means that Leha began to hack computers all over the world. For such zeal boss gave the hacker a vacation of exactly x days. You know the majority of people prefer to go somewhere for a vacation, so Leha immediately went to the travel agency. There he found out that n vouchers left. i-th voucher is characterized by three integers li, ri, costi — day of departure from Vičkopolis, day of arriving back in Vičkopolis and cost of the voucher correspondingly. The duration of the i-th voucher is a value ri - li + 1.At the same time Leha wants to split his own vocation into two parts. Besides he wants to spend as little money as possible. Formally Leha wants to choose exactly two vouchers i and j (i ≠ j) so that they don't intersect, sum of their durations is exactly x and their total cost is as minimal as possible. Two vouchers i and j don't intersect if only at least one of the following conditions is fulfilled: ri < lj or rj < li.Help Leha to choose the necessary vouchers!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"905"While Grisha was celebrating New Year with Ded Moroz, Misha gifted Sasha a small rectangular pond of size n × m, divided into cells of size 1 × 1, inhabited by tiny evil fishes (no more than one fish per cell, otherwise they'll strife!).The gift bundle also includes a square scoop of size r × r, designed for fishing. If the lower-left corner of the scoop-net is located at cell (x, y), all fishes inside the square (x, y)...(x + r - 1, y + r - 1) get caught. Note that the scoop-net should lie completely inside the pond when used.Unfortunately, Sasha is not that skilled in fishing and hence throws the scoop randomly. In order to not frustrate Sasha, Misha decided to release k fishes into the empty pond in such a way that the expected value of the number of caught fishes is as high as possible. Help Misha! In other words, put k fishes in the pond into distinct cells in such a way that when the scoop-net is placed into a random position among (n - r + 1)·(m - r + 1) possible positions, the average number of caught fishes is as high as possible.","['graphs', 'probabilities']","[0, 0, 1, 0, 0, 1, 0, 0]"906"Alyona decided to go on a diet and went to the forest to get some apples. There she unexpectedly found a magic rooted tree with root in the vertex 1, every vertex and every edge of which has a number written on.The girl noticed that some of the tree's vertices are sad, so she decided to play with them. Let's call vertex v sad if there is a vertex u in subtree of vertex v such that dist(v, u) > au, where au is the number written on vertex u, dist(v, u) is the sum of the numbers written on the edges on the path from v to u.Leaves of a tree are vertices connected to a single vertex by a single edge, but the root of a tree is a leaf if and only if the tree consists of a single vertex — root.Thus Alyona decided to remove some of tree leaves until there will be no any sad vertex left in the tree. What is the minimum number of leaves Alyona needs to remove?","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"907"Arthur owns a ski resort on a mountain. There are $$$n$$$ landing spots on the mountain numbered from $$$1$$$ to $$$n$$$ from the top to the foot of the mountain. The spots are connected with one-directional ski tracks. All tracks go towards the foot of the mountain, so there are no directed cycles formed by the tracks. There are at most two tracks leaving each spot, but many tracks may enter the same spot.A skier can start skiing from one spot and stop in another spot if there is a sequence of tracks that lead from the starting spot and end in the ending spot. Unfortunately, recently there were many accidents, because the structure of the resort allows a skier to go through dangerous paths, by reaching high speed and endangering himself and the other customers. Here, a path is called dangerous, if it consists of at least two tracks.Arthur wants to secure his customers by closing some of the spots in a way that there are no dangerous paths in the resort. When a spot is closed, all tracks entering and leaving that spot become unusable. Formally, after closing some of the spots, there should not be a path that consists of two or more tracks.Arthur doesn't want to close too many spots. He will be happy to find any way to close at most $$$\frac{4}{7}n$$$ spots so that the remaining part is safe. Help him find any suitable way to do so.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"908"Mihai has an $$$8 \times 8$$$ chessboard whose rows are numbered from $$$1$$$ to $$$8$$$ from top to bottom and whose columns are numbered from $$$1$$$ to $$$8$$$ from left to right.Mihai has placed exactly one bishop on the chessboard. The bishop is not placed on the edges of the board. (In other words, the row and column of the bishop are between $$$2$$$ and $$$7$$$, inclusive.)The bishop attacks in all directions diagonally, and there is no limit to the distance which the bishop can attack. Note that the cell on which the bishop is placed is also considered attacked.     An example of a bishop on a chessboard. The squares it attacks are marked in red. Mihai has marked all squares the bishop attacks, but forgot where the bishop was! Help Mihai find the position of the bishop.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"909"Nastia has $$$2$$$ positive integers $$$A$$$ and $$$B$$$. She defines that:  The integer is good if it is divisible by $$$A \cdot B$$$;  Otherwise, the integer is nearly good, if it is divisible by $$$A$$$. For example, if $$$A = 6$$$ and $$$B = 4$$$, the integers $$$24$$$ and $$$72$$$ are good, the integers $$$6$$$, $$$660$$$ and $$$12$$$ are nearly good, the integers $$$16$$$, $$$7$$$ are neither good nor nearly good.Find $$$3$$$ different positive integers $$$x$$$, $$$y$$$, and $$$z$$$ such that exactly one of them is good and the other $$$2$$$ are nearly good, and $$$x + y = z$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"910"Iahub is so happy about inventing bubble sort graphs that he's staying all day long at the office and writing permutations. Iahubina is angry that she is no more important for Iahub. When Iahub goes away, Iahubina comes to his office and sabotage his research work.The girl finds an important permutation for the research. The permutation contains n distinct integers a1, a2, ..., an (1 ≤ ai ≤ n). She replaces some of permutation elements with -1 value as a revenge. When Iahub finds out his important permutation is broken, he tries to recover it. The only thing he remembers about the permutation is it didn't have any fixed point. A fixed point for a permutation is an element ak which has value equal to k (ak = k). Your job is to proof to Iahub that trying to recover it is not a good idea. Output the number of permutations which could be originally Iahub's important permutation, modulo 1000000007 (109 + 7).",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"911"While sailing on a boat, Inessa noticed a beautiful water lily flower above the lake's surface. She came closer and it turned out that the lily was exactly $$$H$$$ centimeters above the water surface. Inessa grabbed the flower and sailed the distance of $$$L$$$ centimeters. Exactly at this point the flower touched the water surface.  Suppose that the lily grows at some point $$$A$$$ on the lake bottom, and its stem is always a straight segment with one endpoint at point $$$A$$$. Also suppose that initially the flower was exactly above the point $$$A$$$, i.e. its stem was vertical. Can you determine the depth of the lake at point $$$A$$$?","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"912"You have multiset of n strings of the same length, consisting of lowercase English letters. We will say that those strings are easy to remember if for each string there is some position i and some letter c of the English alphabet, such that this string is the only string in the multiset that has letter c in position i.For example, a multiset of strings {""abc"", ""aba"", ""adc"", ""ada""} are not easy to remember. And multiset {""abc"", ""ada"", ""ssa""} is easy to remember because:   the first string is the only string that has character c in position 3;  the second string is the only string that has character d in position 2;  the third string is the only string that has character s in position 2. You want to change your multiset a little so that it is easy to remember. For aij coins, you can change character in the j-th position of the i-th string into any other lowercase letter of the English alphabet. Find what is the minimum sum you should pay in order to make the multiset of strings easy to remember.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"913"Valera wanted to prepare a Codesecrof round. He's already got one problem and he wants to set a time limit (TL) on it.Valera has written n correct solutions. For each correct solution, he knows its running time (in seconds). Valera has also wrote m wrong solutions and for each wrong solution he knows its running time (in seconds).Let's suppose that Valera will set v seconds TL in the problem. Then we can say that a solution passes the system testing if its running time is at most v seconds. We can also say that a solution passes the system testing with some ""extra"" time if for its running time, a seconds, an inequality 2a ≤ v holds.As a result, Valera decided to set v seconds TL, that the following conditions are met:  v is a positive integer;  all correct solutions pass the system testing;  at least one correct solution passes the system testing with some ""extra"" time;  all wrong solutions do not pass the system testing;  value v is minimum among all TLs, for which points 1, 2, 3, 4 hold. Help Valera and find the most suitable TL or else state that such TL doesn't exist.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"914"You are given an array $$$a$$$ consisting of $$$n$$$ integers. You have to find the length of the smallest (shortest) prefix of elements you need to erase from $$$a$$$ to make it a good array. Recall that the prefix of the array $$$a=[a_1, a_2, \dots, a_n]$$$ is a subarray consisting several first elements: the prefix of the array $$$a$$$ of length $$$k$$$ is the array $$$[a_1, a_2, \dots, a_k]$$$ ($$$0 \le k \le n$$$).The array $$$b$$$ of length $$$m$$$ is called good, if you can obtain a non-decreasing array $$$c$$$ ($$$c_1 \le c_2 \le \dots \le c_{m}$$$) from it, repeating the following operation $$$m$$$ times (initially, $$$c$$$ is empty):  select either the first or the last element of $$$b$$$, remove it from $$$b$$$, and append it to the end of the array $$$c$$$. For example, if we do $$$4$$$ operations: take $$$b_1$$$, then $$$b_{m}$$$, then $$$b_{m-1}$$$ and at last $$$b_2$$$, then $$$b$$$ becomes $$$[b_3, b_4, \dots, b_{m-3}]$$$ and $$$c =[b_1, b_{m}, b_{m-1}, b_2]$$$.Consider the following example: $$$b = [1, 2, 3, 4, 4, 2, 1]$$$. This array is good because we can obtain non-decreasing array $$$c$$$ from it by the following sequence of operations:  take the first element of $$$b$$$, so $$$b = [2, 3, 4, 4, 2, 1]$$$, $$$c = [1]$$$;  take the last element of $$$b$$$, so $$$b = [2, 3, 4, 4, 2]$$$, $$$c = [1, 1]$$$;  take the last element of $$$b$$$, so $$$b = [2, 3, 4, 4]$$$, $$$c = [1, 1, 2]$$$;  take the first element of $$$b$$$, so $$$b = [3, 4, 4]$$$, $$$c = [1, 1, 2, 2]$$$;  take the first element of $$$b$$$, so $$$b = [4, 4]$$$, $$$c = [1, 1, 2, 2, 3]$$$;  take the last element of $$$b$$$, so $$$b = [4]$$$, $$$c = [1, 1, 2, 2, 3, 4]$$$;  take the only element of $$$b$$$, so $$$b = []$$$, $$$c = [1, 1, 2, 2, 3, 4, 4]$$$ — $$$c$$$ is non-decreasing. Note that the array consisting of one element is good.Print the length of the shortest prefix of $$$a$$$ to delete (erase), to make $$$a$$$ to be a good array. Note that the required length can be $$$0$$$.You have to answer $$$t$$$ independent test cases.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"915"Permutation p is an ordered set of integers p1,  p2,  ...,  pn, consisting of n distinct positive integers, each of them doesn't exceed n. We'll denote the i-th element of permutation p as pi. We'll call number n the size or the length of permutation p1,  p2,  ...,  pn.The decreasing coefficient of permutation p1, p2, ..., pn is the number of such i (1 ≤ i < n), that pi > pi + 1.You have numbers n and k. Your task is to print the permutation of length n with decreasing coefficient k.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"916"There are n kangaroos with pockets. Each kangaroo has a size (integer number). A kangaroo can go into another kangaroo's pocket if and only if the size of kangaroo who hold the kangaroo is at least twice as large as the size of kangaroo who is held.Each kangaroo can hold at most one kangaroo, and the kangaroo who is held by another kangaroo cannot hold any kangaroos.The kangaroo who is held by another kangaroo cannot be visible from outside. Please, find a plan of holding kangaroos with the minimal number of kangaroos who is visible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"917"A string t is called an anagram of the string s, if it is possible to rearrange letters in t so that it is identical to the string s. For example, the string ""aab"" is an anagram of the string ""aba"" and the string ""aaa"" is not.The string t is called a substring of the string s if it can be read starting from some position in the string s. For example, the string ""aba"" has six substrings: ""a"", ""b"", ""a"", ""ab"", ""ba"", ""aba"".You are given a string s, consisting of lowercase Latin letters and characters ""?"". You are also given a string p, consisting of lowercase Latin letters only. Let's assume that a string is good if you can obtain an anagram of the string p from it, replacing the ""?"" characters by Latin letters. Each ""?"" can be replaced by exactly one character of the Latin alphabet. For example, if the string p = «aba», then the string ""a??"" is good, and the string «?bc» is not. Your task is to find the number of good substrings of the string s (identical substrings must be counted in the answer several times).",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"918"Today at the lesson of mathematics, Petya learns about the digital root.The digital root of a non-negative integer is the single digit value obtained by an iterative process of summing digits, on each iteration using the result from the previous iteration to compute a digit sum. The process continues until a single-digit number is reached. Let's denote the digital root of $$$x$$$ as $$$S(x)$$$. Then $$$S(5)=5$$$, $$$S(38)=S(3+8=11)=S(1+1=2)=2$$$, $$$S(10)=S(1+0=1)=1$$$.As a homework Petya got $$$n$$$ tasks of the form: find $$$k$$$-th positive number whose digital root is $$$x$$$.Petya has already solved all the problems, but he doesn't know if it's right. Your task is to solve all $$$n$$$ tasks from Petya's homework.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"919"There is the following puzzle popular among nuclear physicists.A reactor contains a set of n atoms of some chemical elements. We shall understand the phrase ""atomic number"" as the number of this atom's element in the periodic table of the chemical elements.You are allowed to take any two different atoms and fuse a new one from them. That results in a new atom, whose number is equal to the sum of the numbers of original atoms. The fusion operation can be performed several times.The aim is getting a new pregiven set of k atoms.The puzzle's difficulty is that it is only allowed to fuse two atoms into one, it is not allowed to split an atom into several atoms. You are suggested to try to solve the puzzle.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"920"Serge came to the school dining room and discovered that there is a big queue here. There are $$$m$$$ pupils in the queue. He's not sure now if he wants to wait until the queue will clear, so he wants to know which dish he will receive if he does. As Serge is very tired, he asks you to compute it instead of him.Initially there are $$$n$$$ dishes with costs $$$a_1, a_2, \ldots, a_n$$$. As you already know, there are the queue of $$$m$$$ pupils who have $$$b_1, \ldots, b_m$$$ togrogs respectively (pupils are enumerated by queue order, i.e the first pupil in the queue has $$$b_1$$$ togrogs and the last one has $$$b_m$$$ togrogs)Pupils think that the most expensive dish is the most delicious one, so every pupil just buys the most expensive dish for which he has money (every dish has a single copy, so when a pupil has bought it nobody can buy it later), and if a pupil doesn't have money for any dish, he just leaves the queue (so brutal capitalism...)But money isn't a problem at all for Serge, so Serge is buying the most expensive dish if there is at least one remaining.Moreover, Serge's school has a very unstable economic situation and the costs of some dishes or number of togrogs of some pupils can change. More formally, you must process $$$q$$$ queries:  change $$$a_i$$$ to $$$x$$$. It means that the price of the $$$i$$$-th dish becomes $$$x$$$ togrogs.  change $$$b_i$$$ to $$$x$$$. It means that the $$$i$$$-th pupil in the queue has $$$x$$$ togrogs now. Nobody leaves the queue during those queries because a saleswoman is late.After every query, you must tell Serge price of the dish which he will buy if he has waited until the queue is clear, or $$$-1$$$ if there are no dishes at this point, according to rules described above.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"921"John Smith knows that his son, Thomas Smith, is among the best students in his class and even in his school. After the students of the school took the exams in English, German, Math, and History, a table of results was formed.There are $$$n$$$ students, each of them has a unique id (from $$$1$$$ to $$$n$$$). Thomas's id is $$$1$$$. Every student has four scores correspond to his or her English, German, Math, and History scores. The students are given in order of increasing of their ids.In the table, the students will be sorted by decreasing the sum of their scores. So, a student with the largest sum will get the first place. If two or more students have the same sum, these students will be sorted by increasing their ids. Please help John find out the rank of his son. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"922"Your friend Ivan asked you to help him rearrange his desktop. The desktop can be represented as a rectangle matrix of size $$$n \times m$$$ consisting of characters '.' (empty cell of the desktop) and '*' (an icon).The desktop is called good if all its icons are occupying some prefix of full columns and, possibly, the prefix of the next column (and there are no icons outside this figure). In other words, some amount of first columns will be filled with icons and, possibly, some amount of first cells of the next (after the last full column) column will be also filled with icons (and all the icons on the desktop belong to this figure). This is pretty much the same as the real life icons arrangement.In one move, you can take one icon and move it to any empty cell in the desktop.Ivan loves to add some icons to his desktop and remove them from it, so he is asking you to answer $$$q$$$ queries: what is the minimum number of moves required to make the desktop good after adding/removing one icon?Note that queries are permanent and change the state of the desktop.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"923"This is an interactive task.Dasha and NN like playing chess. While playing a match they decided that normal chess isn't interesting enough for them, so they invented a game described below.There are $$$666$$$ black rooks and $$$1$$$ white king on the chess board of size $$$999 \times 999$$$. The white king wins if he gets checked by rook, or, in other words, if he moves onto the square which shares either a row or column with a black rook.The sides take turns, starting with white. NN plays as a white king and on each of his turns he moves a king to one of the squares that are adjacent to his current position either by side or diagonally, or, formally, if the king was on the square $$$(x, y)$$$, it can move to the square $$$(nx, ny)$$$ if and only $$$\max (|nx - x|, |ny - y|) = 1$$$ , $$$1 \leq nx, ny \leq 999$$$. NN is also forbidden from moving onto the squares occupied with black rooks, however, he can move onto the same row or column as a black rook.Dasha, however, neglects playing by the chess rules, and instead of moving rooks normally she moves one of her rooks on any space devoid of other chess pieces. It is also possible that the rook would move onto the same square it was before and the position wouldn't change. However, she can't move the rook on the same row or column with the king.Each player makes $$$2000$$$ turns, if the white king wasn't checked by a black rook during those turns, black wins. NN doesn't like losing, but thinks the task is too difficult for him, so he asks you to write a program that will always win playing for the white king. Note that Dasha can see your king and play depending on its position.",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"924"The Fair Nut is going to travel to the Tree Country, in which there are $$$n$$$ cities. Most of the land of this country is covered by forest. Furthermore, the local road system forms a tree (connected graph without cycles). Nut wants to rent a car in the city $$$u$$$ and go by a simple path to city $$$v$$$. He hasn't determined the path, so it's time to do it. Note that chosen path can consist of only one vertex.A filling station is located in every city. Because of strange law, Nut can buy only $$$w_i$$$ liters of gasoline in the $$$i$$$-th city. We can assume, that he has infinite money. Each road has a length, and as soon as Nut drives through this road, the amount of gasoline decreases by length. Of course, Nut can't choose a path, which consists of roads, where he runs out of gasoline. He can buy gasoline in every visited city, even in the first and the last.He also wants to find the maximum amount of gasoline that he can have at the end of the path. Help him: count it.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"925"Gottfried learned about binary number representation. He then came up with this task and presented it to you.You are given a collection of $$$n$$$ non-negative integers $$$a_1, \ldots, a_n$$$. You are allowed to perform the following operation: choose two distinct indices $$$1 \leq i, j \leq n$$$. If before the operation $$$a_i = x$$$, $$$a_j = y$$$, then after the operation $$$a_i = x~\mathsf{AND}~y$$$, $$$a_j = x~\mathsf{OR}~y$$$, where $$$\mathsf{AND}$$$ and $$$\mathsf{OR}$$$ are bitwise AND and OR respectively (refer to the Notes section for formal description). The operation may be performed any number of times (possibly zero).After all operations are done, compute $$$\sum_{i=1}^n a_i^2$$$ — the sum of squares of all $$$a_i$$$. What is the largest sum of squares you can achieve?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"926"You are given a tree (an undirected connected graph without cycles) and an integer $$$s$$$.Vanya wants to put weights on all edges of the tree so that all weights are non-negative real numbers and their sum is $$$s$$$. At the same time, he wants to make the diameter of the tree as small as possible.Let's define the diameter of a weighed tree as the maximum sum of the weights of the edges lying on the path between two some vertices of the tree. In other words, the diameter of a weighed tree is the length of the longest simple path in the tree, where length of a path is equal to the sum of weights over all edges in the path.Find the minimum possible diameter that Vanya can get.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"927"Colonel has n badges. He wants to give one badge to every of his n soldiers. Each badge has a coolness factor, which shows how much it's owner reached. Coolness factor can be increased by one for the cost of one coin. For every pair of soldiers one of them should get a badge with strictly higher factor than the second one. Exact values of their factors aren't important, they just need to have distinct factors. Colonel knows, which soldier is supposed to get which badge initially, but there is a problem. Some of badges may have the same factor of coolness. Help him and calculate how much money has to be paid for making all badges have different factors of coolness.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"928"Berland State University has received a new update for the operating system. Initially it is installed only on the $$$1$$$-st computer.Update files should be copied to all $$$n$$$ computers. The computers are not connected to the internet, so the only way to transfer update files from one computer to another is to copy them using a patch cable (a cable connecting two computers directly). Only one patch cable can be connected to a computer at a time. Thus, from any computer where the update files are installed, they can be copied to some other computer in exactly one hour.Your task is to find the minimum number of hours required to copy the update files to all $$$n$$$ computers if there are only $$$k$$$ patch cables in Berland State University.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"929"Polycarp has a poor memory. Each day he can remember no more than $$$3$$$ of different letters. Polycarp wants to write a non-empty string of $$$s$$$ consisting of lowercase Latin letters, taking minimum number of days. In how many days will he be able to do it?Polycarp initially has an empty string and can only add characters to the end of that string.For example, if Polycarp wants to write the string lollipops, he will do it in $$$2$$$ days:   on the first day Polycarp will memorize the letters l, o, i and write lolli;  On the second day Polycarp will remember the letters p, o, s, add pops to the resulting line and get the line lollipops. If Polycarp wants to write the string stringology, he will do it in $$$4$$$ days:   in the first day will be written part str;  on day two will be written part ing;  on the third day, part of olog will be written;  on the fourth day, part of y will be written. For a given string $$$s$$$, print the minimum number of days it will take Polycarp to write it.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"930"You are given a rooted tree consisting of n vertices. Each vertex has a number written on it; number ai is written on vertex i.Let's denote d(i, j) as the distance between vertices i and j in the tree (that is, the number of edges in the shortest path from i to j). Also let's denote the k-blocked subtree of vertex x as the set of vertices y such that both these conditions are met:  x is an ancestor of y (every vertex is an ancestor of itself);  d(x, y) ≤ k. You are given m queries to the tree. i-th query is represented by two numbers xi and ki, and the answer to this query is the minimum value of aj among such vertices j such that j belongs to ki-blocked subtree of xi.Write a program that would process these queries quickly!Note that the queries are given in a modified way.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"931"A queen is the strongest chess piece. In modern chess the queen can move any number of squares in any horizontal, vertical or diagonal direction (considering that there're no other pieces on its way). The queen combines the options given to the rook and the bishop.There are m queens on a square n × n chessboard. You know each queen's positions, the i-th queen is positioned in the square (ri, ci), where ri is the board row number (numbered from the top to the bottom from 1 to n), and ci is the board's column number (numbered from the left to the right from 1 to n). No two queens share the same position.For each queen one can count w — the number of other queens that the given queen threatens (attacks). For a fixed attack direction only the first queen in this direction is under attack if there are many queens are on the ray of the attack. Obviously, for any queen w is between 0 and 8, inclusive.Print the sequence t0, t1, ..., t8, where ti is the number of queens that threaten exactly i other queens, i.e. the number of queens that their w equals i.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"932"Yaroslav is playing a game called ""Time"". The game has a timer showing the lifespan he's got left. As soon as the timer shows 0, Yaroslav's character dies and the game ends. Also, the game has n clock stations, station number i is at point (xi, yi) of the plane. As the player visits station number i, he increases the current time on his timer by ai. The stations are for one-time use only, so if the player visits some station another time, the time on his timer won't grow.A player spends d·dist time units to move between stations, where dist is the distance the player has covered and d is some constant. The distance between stations i and j is determined as |xi - xj| + |yi - yj|.Initially, the player is at station number 1, and the player has strictly more than zero and strictly less than one units of time. At station number 1 one unit of money can increase the time on the timer by one time unit (you can buy only integer number of time units).Now Yaroslav is wondering, how much money he needs to get to station n. Help Yaroslav. Consider the time to buy and to increase the timer value negligibly small.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"933"A multi-subject competition is coming! The competition has $$$m$$$ different subjects participants can choose from. That's why Alex (the coach) should form a competition delegation among his students. He has $$$n$$$ candidates. For the $$$i$$$-th person he knows subject $$$s_i$$$ the candidate specializes in and $$$r_i$$$ — a skill level in his specialization (this level can be negative!). The rules of the competition require each delegation to choose some subset of subjects they will participate in. The only restriction is that the number of students from the team participating in each of the chosen subjects should be the same.Alex decided that each candidate would participate only in the subject he specializes in. Now Alex wonders whom he has to choose to maximize the total sum of skill levels of all delegates, or just skip the competition this year if every valid non-empty delegation has negative sum.(Of course, Alex doesn't have any spare money so each delegate he chooses must participate in the competition).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"934"This is the easy version of the problem. The only difference between the versions is the constraints on $$$n$$$, $$$k$$$, $$$a_i$$$, and the sum of $$$n$$$ over all test cases. You can make hacks only if both versions of the problem are solved.Note the unusual memory limit.You are given an array of integers $$$a_1, a_2, \ldots, a_n$$$ of length $$$n$$$, and an integer $$$k$$$.The cost of an array of integers $$$p_1, p_2, \ldots, p_n$$$ of length $$$n$$$ is $$$$$$\max\limits_{1 \le i \le n}\left(\left \lfloor \frac{a_i}{p_i} \right \rfloor \right) - \min\limits_{1 \le i \le n}\left(\left \lfloor \frac{a_i}{p_i} \right \rfloor \right).$$$$$$Here, $$$\lfloor \frac{x}{y} \rfloor$$$ denotes the integer part of the division of $$$x$$$ by $$$y$$$. Find the minimum cost of an array $$$p$$$ such that $$$1 \le p_i \le k$$$ for all $$$1 \le i \le n$$$.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"935You are given a connected undirected graph consisting of $$$n$$$ vertices and $$$m$$$ edges. There are no self-loops or multiple edges in the given graph.You have to direct its edges in such a way that the obtained directed graph does not contain any paths of length two or greater (where the length of path is denoted as the number of traversed edges).,['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"936"Now Dmitry has a session, and he has to pass $$$n$$$ exams. The session starts on day $$$1$$$ and lasts $$$d$$$ days. The $$$i$$$th exam will take place on the day of $$$a_i$$$ ($$$1 \le a_i \le d$$$), all $$$a_i$$$ — are different.    Sample, where $$$n=3$$$, $$$d=12$$$, $$$a=[3,5,9]$$$. Orange — exam days. Before the first exam Dmitry will rest $$$2$$$ days, before the second he will rest $$$1$$$ day and before the third he will rest $$$3$$$ days. For the session schedule, Dmitry considers a special value $$$\mu$$$ — the smallest of the rest times before the exam for all exams. For example, for the image above, $$$\mu=1$$$. In other words, for the schedule, he counts exactly $$$n$$$ numbers  — how many days he rests between the exam $$$i-1$$$ and $$$i$$$ (for $$$i=0$$$ between the start of the session and the exam $$$i$$$). Then it finds $$$\mu$$$ — the minimum among these $$$n$$$ numbers.Dmitry believes that he can improve the schedule of the session. He may ask to change the date of one exam (change one arbitrary value of $$$a_i$$$). Help him change the date so that all $$$a_i$$$ remain different, and the value of $$$\mu$$$ is as large as possible.For example, for the schedule above, it is most advantageous for Dmitry to move the second exam to the very end of the session. The new schedule will take the form:    Now the rest periods before exams are equal to $$$[2,2,5]$$$. So, $$$\mu=2$$$. Dmitry can leave the proposed schedule unchanged (if there is no way to move one exam so that it will lead to an improvement in the situation).",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"937"This is an interactive problem. Remember to flush your output while communicating with the testing program. You may use fflush(stdout) in C++, system.out.flush() in Java, stdout.flush() in Python or flush(output) in Pascal to flush the output. If you use some other programming language, consult its documentation. You may also refer to the guide on interactive problems: https://codeforces.com/blog/entry/45307.The jury has chosen a string $$$s$$$ consisting of $$$n$$$ characters; each character of $$$s$$$ is a lowercase Latin letter. Your task is to guess this string; initially, you know only its length.You may ask queries of two types:  $$$1$$$ $$$i$$$ — the query of the first type, where $$$i$$$ is an integer from $$$1$$$ to $$$n$$$. In response to this query, the jury will tell you the character $$$s_i$$$;  $$$2$$$ $$$l$$$ $$$r$$$ — the query of the second type, where $$$l$$$ and $$$r$$$ are integers such that $$$1 \le l \le r \le n$$$. In response to this query, the jury will tell you the number of different characters among $$$s_l, s_{l+1}, \dots, s_r$$$. You are allowed to ask no more than $$$26$$$ queries of the first type, and no more than $$$6000$$$ queries of the second type. Your task is to restore the string $$$s$$$.For each test in this problem, the string $$$s$$$ is fixed beforehand, and will be the same for every submission.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"938"Leha like all kinds of strange things. Recently he liked the function F(n, k). Consider all possible k-element subsets of the set [1, 2, ..., n]. For subset find minimal element in it. F(n, k) — mathematical expectation of the minimal element among all k-element subsets.But only function does not interest him. He wants to do interesting things with it. Mom brought him two arrays A and B, each consists of m integers. For all i, j such that 1 ≤ i, j ≤ m the condition Ai ≥ Bj holds. Help Leha rearrange the numbers in the array A so that the sum  is maximally possible, where A' is already rearranged array.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"939"When registering in a social network, users are allowed to create their own convenient login to make it easier to share contacts, print it on business cards, etc.Login is an arbitrary sequence of lower and uppercase latin letters, digits and underline symbols («_»). However, in order to decrease the number of frauds and user-inattention related issues, it is prohibited to register a login if it is similar with an already existing login. More precisely, two logins s and t are considered similar if we can transform s to t via a sequence of operations of the following types:   transform lowercase letters to uppercase and vice versa;  change letter «O» (uppercase latin letter) to digit «0» and vice versa;  change digit «1» (one) to any letter among «l» (lowercase latin «L»), «I» (uppercase latin «i») and vice versa, or change one of these letters to other. For example, logins «Codeforces» and «codef0rces» as well as «OO0OOO00O0OOO0O00OOO0OO_lol» and «OO0OOO0O00OOO0O00OO0OOO_1oI» are considered similar whereas «Codeforces» and «Code_forces» are not.You're given a list of existing logins with no two similar amonst and a newly created user login. Check whether this new login is similar with any of the existing ones.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"940"Niwel is a little golden bear. As everyone knows, bears live in forests, but Niwel got tired of seeing all the trees so he decided to move to the city.In the city, Niwel took on a job managing bears to deliver goods. The city that he lives in can be represented as a directed graph with n nodes and m edges. Each edge has a weight capacity. A delivery consists of a bear carrying weights with their bear hands on a simple path from node 1 to node n. The total weight that travels across a particular edge must not exceed the weight capacity of that edge.Niwel has exactly x bears. In the interest of fairness, no bear can rest, and the weight that each bear carries must be exactly the same. However, each bear may take different paths if they like.Niwel would like to determine, what is the maximum amount of weight he can deliver (it's the sum of weights carried by bears). Find the maximum weight.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"941"Given an array $$$a$$$ of length $$$n$$$, you can do at most $$$k$$$ operations of the following type on it:  choose $$$2$$$ different elements in the array, add $$$1$$$ to the first, and subtract $$$1$$$ from the second. However, all the elements of $$$a$$$ have to remain non-negative after this operation. What is lexicographically the smallest array you can obtain?An array $$$x$$$ is lexicographically smaller than an array $$$y$$$ if there exists an index $$$i$$$ such that $$$x_i<y_i$$$, and $$$x_j=y_j$$$ for all $$$1 \le j < i$$$. Less formally, at the first index $$$i$$$ in which they differ, $$$x_i<y_i$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"942"The only difference between easy and hard versions is that you should complete all the projects in easy version but this is not necessary in hard version.Polycarp is a very famous freelancer. His current rating is $$$r$$$ units.Some very rich customers asked him to complete some projects for their companies. To complete the $$$i$$$-th project, Polycarp needs to have at least $$$a_i$$$ units of rating; after he completes this project, his rating will change by $$$b_i$$$ (his rating will increase or decrease by $$$b_i$$$) ($$$b_i$$$ can be positive or negative). Polycarp's rating should not fall below zero because then people won't trust such a low rated freelancer.Is it possible to complete all the projects? Formally, write a program to check if such an order of the projects exists, that Polycarp has enough rating before starting each project, and he has non-negative rating after completing each project.In other words, you have to check that there exists such an order of projects in which Polycarp will complete them, so he has enough rating before starting each project, and has non-negative rating after completing each project.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"943"There are $$$n$$$ models in the shop numbered from $$$1$$$ to $$$n$$$, with sizes $$$s_1, s_2, \ldots, s_n$$$.Orac will buy some of the models and will arrange them in the order of increasing numbers (i.e. indices, but not sizes).Orac thinks that the obtained arrangement is beatiful, if for any two adjacent models with indices $$$i_j$$$ and $$$i_{j+1}$$$ (note that $$$i_j < i_{j+1}$$$, because Orac arranged them properly), $$$i_{j+1}$$$ is divisible by $$$i_j$$$ and $$$s_{i_j} < s_{i_{j+1}}$$$.For example, for $$$6$$$ models with sizes $$$\{3, 6, 7, 7, 7, 7\}$$$, he can buy models with indices $$$1$$$, $$$2$$$, and $$$6$$$, and the obtained arrangement will be beautiful. Also, note that the arrangement with exactly one model is also considered beautiful.Orac wants to know the maximum number of models that he can buy, and he may ask you these queries many times.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"944"You have a rooted tree consisting of n vertices. Let's number them with integers from 1 to n inclusive. The root of the tree is the vertex 1. For each i > 1 direct parent of the vertex i is pi. We say that vertex i is child for its direct parent pi.You have initially painted all the vertices with red color. You like to repaint some vertices of the tree. To perform painting you use the function paint that you call with the root of the tree as an argument. Here is the pseudocode of this function:count = 0 // global integer variable rnd() { // this function is used in paint code    return 0 or 1 equiprobably}paint(s) {    if (count is even) then paint s with white color    else paint s with black color    count = count + 1        if rnd() = 1 then children = [array of vertex s children in ascending order of their numbers]    else children = [array of vertex s children in descending order of their numbers]    for child in children { // iterating over children array        if rnd() = 1 then paint(child) // calling paint recursively    }}As a result of this function, some vertices may change their colors to white or black and some of them may remain red.Your task is to determine the number of distinct possible colorings of the vertices of the tree. We will assume that the coloring is possible if there is a nonzero probability to get this coloring with a single call of paint(1). We assume that the colorings are different if there is a pair of vertices that are painted with different colors in these colorings. Since the required number may be very large, find its remainder of division by 1000000007 (109 + 7).",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"945"The Fair Nut found a string $$$s$$$. The string consists of lowercase Latin letters. The Nut is a curious guy, so he wants to find the number of strictly increasing sequences $$$p_1, p_2, \ldots, p_k$$$, such that:   For each $$$i$$$ ($$$1 \leq i \leq k$$$), $$$s_{p_i} =$$$ 'a'.  For each $$$i$$$ ($$$1 \leq i < k$$$), there is such $$$j$$$ that $$$p_i < j < p_{i + 1}$$$ and $$$s_j =$$$ 'b'. The Nut is upset because he doesn't know how to find the number. Help him.This number should be calculated modulo $$$10^9 + 7$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"946"Alice is playing with some stones.Now there are three numbered heaps of stones. The first of them contains $$$a$$$ stones, the second of them contains $$$b$$$ stones and the third of them contains $$$c$$$ stones.Each time she can do one of two operations:  take one stone from the first heap and two stones from the second heap (this operation can be done only if the first heap contains at least one stone and the second heap contains at least two stones);  take one stone from the second heap and two stones from the third heap (this operation can be done only if the second heap contains at least one stone and the third heap contains at least two stones). She wants to get the maximum number of stones, but she doesn't know what to do. Initially, she has $$$0$$$ stones. Can you help her?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"947"Okabe likes to be able to walk through his city on a path lit by street lamps. That way, he doesn't get beaten up by schoolchildren.Okabe's city is represented by a 2D grid of cells. Rows are numbered from 1 to n from top to bottom, and columns are numbered 1 to m from left to right. Exactly k cells in the city are lit by a street lamp. It's guaranteed that the top-left cell is lit.Okabe starts his walk from the top-left cell, and wants to reach the bottom-right cell. Of course, Okabe will only walk on lit cells, and he can only move to adjacent cells in the up, down, left, and right directions. However, Okabe can also temporarily light all the cells in any single row or column at a time if he pays 1 coin, allowing him to walk through some cells not lit initially. Note that Okabe can only light a single row or column at a time, and has to pay a coin every time he lights a new row or column. To change the row or column that is temporarily lit, he must stand at a cell that is lit initially. Also, once he removes his temporary light from a row or column, all cells in that row/column not initially lit are now not lit.Help Okabe find the minimum number of coins he needs to pay to complete his walk!",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"948"You are playing a computer game. In this game, you have to fight $$$n$$$ monsters.To defend from monsters, you need a shield. Each shield has two parameters: its current durability $$$a$$$ and its defence rating $$$b$$$. Each monster has only one parameter: its strength $$$d$$$.When you fight a monster with strength $$$d$$$ while having a shield with current durability $$$a$$$ and defence $$$b$$$, there are three possible outcomes:  if $$$a = 0$$$, then you receive $$$d$$$ damage;  if $$$a > 0$$$ and $$$d \ge b$$$, you receive no damage, but the current durability of the shield decreases by $$$1$$$;  if $$$a > 0$$$ and $$$d < b$$$, nothing happens. The $$$i$$$-th monster has strength $$$d_i$$$, and you will fight each of the monsters exactly once, in some random order (all $$$n!$$$ orders are equiprobable). You have to consider $$$m$$$ different shields, the $$$i$$$-th shield has initial durability $$$a_i$$$ and defence rating $$$b_i$$$. For each shield, calculate the expected amount of damage you will receive if you take this shield and fight the given $$$n$$$ monsters in random order.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"949"There is a given string S consisting of N symbols. Your task is to find the number of ordered pairs of integers i and j such that1. 1 ≤ i, j ≤ N2. S[i] = S[j], that is the i-th symbol of string S is equal to the j-th.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"950"Chef Monocarp has just put $$$n$$$ dishes into an oven. He knows that the $$$i$$$-th dish has its optimal cooking time equal to $$$t_i$$$ minutes.At any positive integer minute $$$T$$$ Monocarp can put no more than one dish out of the oven. If the $$$i$$$-th dish is put out at some minute $$$T$$$, then its unpleasant value is $$$|T - t_i|$$$ — the absolute difference between $$$T$$$ and $$$t_i$$$. Once the dish is out of the oven, it can't go back in.Monocarp should put all the dishes out of the oven. What is the minimum total unpleasant value Monocarp can obtain?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"951"Johnny has just found the new, great tutorial: ""How to become a grandmaster?"". The tutorial tells many strange and unexpected for Johnny things, such as you have to be patient or that very important is solving many harder and harder problems. The boy has found an online judge with tasks divided by topics they cover. He has picked $$$p^{k_i}$$$ problems from $$$i$$$-th category ($$$p$$$ is his favorite number). He wants to solve them in two weeks (the patience condition is too hard for Johnny, so for simplicity, he looks only at easy tasks, which can be solved in such a period). Now our future grandmaster has to decide which topics to cover first and which the second week. Help him assign topics in such a way, that workload is balanced.Formally, given $$$n$$$ numbers $$$p^{k_i}$$$, the boy wants to divide them into two disjoint sets, minimizing the absolute difference between sums of numbers in each set. Find the minimal absolute difference. Output the result modulo $$$10^{9}+7$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"952"Little Artyom decided to study probability theory. He found a book with a lot of nice exercises and now wants you to help him with one of them.Consider two dices. When thrown each dice shows some integer from 1 to n inclusive. For each dice the probability of each outcome is given (of course, their sum is 1), and different dices may have different probability distributions.We throw both dices simultaneously and then calculate values max(a, b) and min(a, b), where a is equal to the outcome of the first dice, while b is equal to the outcome of the second dice. You don't know the probability distributions for particular values on each dice, but you know the probability distributions for max(a, b) and min(a, b). That is, for each x from 1 to n you know the probability that max(a, b) would be equal to x and the probability that min(a, b) would be equal to x. Find any valid probability distribution for values on the dices. It's guaranteed that the input data is consistent, that is, at least one solution exists.","['math', 'probabilities']","[0, 0, 0, 1, 0, 1, 0, 0]"953"Binary Spiders are species of spiders that live on Mars. These spiders weave their webs to defend themselves from enemies.To weave a web, spiders join in pairs. If the first spider in pair has $$$x$$$ legs, and the second spider has $$$y$$$ legs, then they weave a web with durability $$$x \oplus y$$$. Here, $$$\oplus$$$ means bitwise XOR.Binary Spiders live in large groups. You observe a group of $$$n$$$ spiders, and the $$$i$$$-th spider has $$$a_i$$$ legs.When the group is threatened, some of the spiders become defenders. Defenders are chosen in the following way. First, there must be at least two defenders. Second, any pair of defenders must be able to weave a web with durability at least $$$k$$$. Third, there must be as much defenders as possible.Scientists have researched the behaviour of Binary Spiders for a long time, and now they have a hypothesis that they can always choose the defenders in an optimal way, satisfying the conditions above. You need to verify this hypothesis on your group of spiders. So, you need to understand how many spiders must become defenders. You are not a Binary Spider, so you decided to use a computer to solve this problem.","['math', 'trees']","[0, 0, 0, 1, 0, 0, 0, 1]"954"You are given a list of $$$n$$$ integers. You can perform the following operation: you choose an element $$$x$$$ from the list, erase $$$x$$$ from the list, and subtract the value of $$$x$$$ from all the remaining elements. Thus, in one operation, the length of the list is decreased by exactly $$$1$$$.Given an integer $$$k$$$ ($$$k>0$$$), find if there is some sequence of $$$n-1$$$ operations such that, after applying the operations, the only remaining element of the list is equal to $$$k$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"955"Burenka is about to watch the most interesting sporting event of the year — a fighting tournament organized by her friend Tonya.$$$n$$$ athletes participate in the tournament, numbered from $$$1$$$ to $$$n$$$. Burenka determined the strength of the $$$i$$$-th athlete as an integer $$$a_i$$$, where $$$1 \leq a_i \leq n$$$. All the strength values are different, that is, the array $$$a$$$ is a permutation of length $$$n$$$. We know that in a fight, if $$$a_i > a_j$$$, then the $$$i$$$-th participant always wins the $$$j$$$-th.The tournament goes like this: initially, all $$$n$$$ athletes line up in ascending order of their ids, and then there are infinitely many fighting rounds. In each round there is exactly one fight: the first two people in line come out and fight. The winner goes back to the front of the line, and the loser goes to the back.Burenka decided to ask Tonya $$$q$$$ questions. In each question, Burenka asks how many victories the $$$i$$$-th participant gets in the first $$$k$$$ rounds of the competition for some given numbers $$$i$$$ and $$$k$$$. Tonya is not very good at analytics, so he asks you to help him answer all the questions.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"956"Lesha plays the recently published new version of the legendary game hacknet. In this version character skill mechanism was introduced. Now, each player character has exactly n skills. Each skill is represented by a non-negative integer ai — the current skill level. All skills have the same maximum level A.Along with the skills, global ranking of all players was added. Players are ranked according to the so-called Force. The Force of a player is the sum of the following values:  The number of skills that a character has perfected (i.e., such that ai = A), multiplied by coefficient cf. The minimum skill level among all skills (min ai), multiplied by coefficient cm. Now Lesha has m hacknetian currency units, which he is willing to spend. Each currency unit can increase the current level of any skill by 1 (if it's not equal to A yet). Help him spend his money in order to achieve the maximum possible value of the Force.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"957"Given an array $$$a$$$ of $$$n$$$ integers, find a range of values $$$[x, y]$$$ ($$$x \le y$$$), and split $$$a$$$ into exactly $$$k$$$ ($$$1 \le k \le n$$$) subarrays in such a way that:  Each subarray is formed by several continuous elements of $$$a$$$, that is, it is equal to $$$a_l, a_{l+1}, \ldots, a_r$$$ for some $$$l$$$ and $$$r$$$ ($$$1 \leq l \leq r \leq n$$$).  Each element from $$$a$$$ belongs to exactly one subarray.  In each subarray the number of elements inside the range $$$[x, y]$$$ (inclusive) is strictly greater than the number of elements outside the range. An element with index $$$i$$$ is inside the range $$$[x, y]$$$ if and only if $$$x \le a_i \le y$$$.  Print any solution that minimizes $$$y - x$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"958"International Abbreviation Olympiad takes place annually starting from 1989. Each year the competition receives an abbreviation of form IAO'y, where y stands for some number of consequent last digits of the current year. Organizers always pick an abbreviation with non-empty string y that has never been used before. Among all such valid abbreviations they choose the shortest one and announce it to be the abbreviation of this year's competition.For example, the first three Olympiads (years 1989, 1990 and 1991, respectively) received the abbreviations IAO'9, IAO'0 and IAO'1, while the competition in 2015 received an abbreviation IAO'15, as IAO'5 has been already used in 1995.You are given a list of abbreviations. For each of them determine the year it stands for.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"959"It's now 260 AD. Shapur, being extremely smart, became the King of Persia. He is now called Shapur, His majesty King of kings of Iran and Aniran.Recently the Romans declared war on Persia. They dreamed to occupy Armenia. In the recent war, the Romans were badly defeated. Now their senior army general, Philip is captured by Shapur and Shapur is now going to capture Valerian, the Roman emperor.Being defeated, the cowardly Valerian hid in a room at the top of one of his castles. To capture him, Shapur has to open many doors. Fortunately Valerian was too scared to make impenetrable locks for the doors.Each door has 4 parts. The first part is an integer number a. The second part is either an integer number b or some really odd sign which looks like R. The third one is an integer c and the fourth part is empty! As if it was laid for writing something. Being extremely gifted, after opening the first few doors, Shapur found out the secret behind the locks.c is an integer written in base a, to open the door we should write it in base b. The only bad news is that this R is some sort of special numbering system that is used only in Roman empire, so opening the doors is not just a piece of cake!Here's an explanation of this really weird number system that even doesn't have zero:Roman numerals are based on seven symbols: a stroke (identified with the letter I) for a unit, a chevron (identified with the letter V) for a five, a cross-stroke (identified with the letter X) for a ten, a C (identified as an abbreviation of Centum) for a hundred, etc.: I=1 V=5 X=10 L=50 C=100 D=500 M=1000Symbols are iterated to produce multiples of the decimal (1, 10, 100, 1, 000) values, with V, L, D substituted for a multiple of five, and the iteration continuing: I 1, II 2, III 3, V 5, VI 6, VII 7, etc., and the same for other bases: X 10, XX 20, XXX 30, L 50, LXXX 80; CC 200, DCC 700, etc. At the fourth and ninth iteration, a subtractive principle must be employed, with the base placed before the higher base: IV 4, IX 9, XL 40, XC 90, CD 400, CM 900.Also in bases greater than 10 we use A for 10, B for 11, etc.Help Shapur capture Valerian and bring peace back to Persia, especially Armenia.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"960"Uh oh! Ray lost his array yet again! However, Omkar might be able to help because he thinks he has found the OmkArray of Ray's array. The OmkArray of an array $$$a$$$ with elements $$$a_1, a_2, \ldots, a_{2k-1}$$$, is the array $$$b$$$ with elements $$$b_1, b_2, \ldots, b_{k}$$$ such that $$$b_i$$$ is equal to the median of $$$a_1, a_2, \ldots, a_{2i-1}$$$ for all $$$i$$$. Omkar has found an array $$$b$$$ of size $$$n$$$ ($$$1 \leq n \leq 2 \cdot 10^5$$$, $$$-10^9 \leq b_i \leq 10^9$$$). Given this array $$$b$$$, Ray wants to test Omkar's claim and see if $$$b$$$ actually is an OmkArray of some array $$$a$$$. Can you help Ray?The median of a set of numbers $$$a_1, a_2, \ldots, a_{2i-1}$$$ is the number $$$c_{i}$$$ where $$$c_{1}, c_{2}, \ldots, c_{2i-1}$$$ represents $$$a_1, a_2, \ldots, a_{2i-1}$$$ sorted in nondecreasing order. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"961"The symbol $$$\wedge$$$ is quite ambiguous, especially when used without context. Sometimes it is used to denote a power ($$$a\wedge b = a^b$$$) and sometimes it is used to denote the XOR operation ($$$a\wedge b=a\oplus b$$$). You have an ambiguous expression $$$E=A_1\wedge A_2\wedge A_3\wedge\ldots\wedge A_n$$$. You can replace each $$$\wedge$$$ symbol with either a $$$\texttt{Power}$$$ operation or a $$$\texttt{XOR}$$$ operation to get an unambiguous expression $$$E'$$$.The value of this expression $$$E'$$$ is determined according to the following rules:   All $$$\texttt{Power}$$$ operations are performed before any $$$\texttt{XOR}$$$ operation. In other words, the $$$\texttt{Power}$$$ operation takes precedence over $$$\texttt{XOR}$$$ operation. For example, $$$4\;\texttt{XOR}\;6\;\texttt{Power}\;2=4\oplus (6^2)=4\oplus 36=32$$$.  Consecutive powers are calculated from left to right. For example, $$$2\;\texttt{Power}\;3 \;\texttt{Power}\;4 = (2^3)^4 = 8^4 = 4096$$$. You are given an array $$$B$$$ of length $$$n$$$ and an integer $$$k$$$. The array $$$A$$$ is given by $$$A_i=2^{B_i}$$$ and the expression $$$E$$$ is given by $$$E=A_1\wedge A_2\wedge A_3\wedge\ldots\wedge A_n$$$. You need to find the XOR of the values of all possible unambiguous expressions $$$E'$$$ which can be obtained from $$$E$$$ and has at least $$$k$$$ $$$\wedge$$$ symbols used as $$$\texttt{XOR}$$$ operation. Since the answer can be very large, you need to find it modulo $$$2^{2^{20}}$$$. Since this number can also be very large, you need to print its binary representation without leading zeroes. If the answer is equal to $$$0$$$, print $$$0$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"962"The only difference between easy and hard versions is constraints.You are given $$$n$$$ segments on the coordinate axis $$$OX$$$. Segments can intersect, lie inside each other and even coincide. The $$$i$$$-th segment is $$$[l_i; r_i]$$$ ($$$l_i \le r_i$$$) and it covers all integer points $$$j$$$ such that $$$l_i \le j \le r_i$$$.The integer point is called bad if it is covered by strictly more than $$$k$$$ segments.Your task is to remove the minimum number of segments so that there are no bad points at all.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"963"On Bertown's main street n trees are growing, the tree number i has the height of ai meters (1 ≤ i ≤ n). By the arrival of the President of Berland these trees were decided to be changed so that their heights formed a beautiful sequence. This means that the heights of trees on ends (the 1st one and the n-th one) should be equal to each other, the heights of the 2-nd and the (n - 1)-th tree must also be equal to each other, at that the height of the 2-nd tree should be larger than the height of the first tree by 1, and so on. In other words, the heights of the trees, standing at equal distance from the edge (of one end of the sequence) must be equal to each other, and with the increasing of the distance from the edge by 1 the tree height must also increase by 1. For example, the sequences ""2 3 4 5 5 4 3 2"" and ""1 2 3 2 1"" are beautiful, and '1 3 3 1"" and ""1 2 3 1"" are not. Changing the height of a tree is a very expensive operation, using advanced technologies invented by Berland scientists. In one operation you can choose any tree and change its height to any number, either increase or decrease. Note that even after the change the height should remain a positive integer, i. e, it can't be less than or equal to zero. Identify the smallest number of changes of the trees' height needed for the sequence of their heights to become beautiful.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"964"Once upon a time, Oolimry saw a suffix array. He wondered how many strings can produce this suffix array. More formally, given a suffix array of length $$$n$$$ and having an alphabet size $$$k$$$, count the number of strings that produce such a suffix array. Let $$$s$$$ be a string of length $$$n$$$. Then the $$$i$$$-th suffix of $$$s$$$ is the substring $$$s[i \ldots n-1]$$$. A suffix array is the array of integers that represent the starting indexes of all the suffixes of a given string, after the suffixes are sorted in the lexicographic order. For example, the suffix array of oolimry is $$$[3,2,4,1,0,5,6]$$$ as the array of sorted suffixes is $$$[\texttt{imry},\texttt{limry},\texttt{mry},\texttt{olimry},\texttt{oolimry},\texttt{ry},\texttt{y}]$$$. A string $$$x$$$ is lexicographically smaller than string $$$y$$$, if either $$$x$$$ is a prefix of $$$y$$$ (and $$$x\neq y$$$), or there exists such $$$i$$$ that $$$x_i < y_i$$$, and for any $$$1\leq j < i$$$ , $$$x_j = y_j$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"965"The police department of your city has just started its journey. Initially, they don’t have any manpower. So, they started hiring new recruits in groups.Meanwhile, crimes keeps occurring within the city. One member of the police force can investigate only one crime during his/her lifetime.If there is no police officer free (isn't busy with crime) during the occurrence of a crime, it will go untreated.Given the chronological order of crime occurrences and recruit hirings, find the number of crimes which will go untreated.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"966"Mr. Scrooge, a very busy man, decided to count the time he wastes on all sorts of useless stuff to evaluate the lost profit. He has already counted the time he wastes sleeping and eating. And now Mr. Scrooge wants to count the time he has wasted signing papers.Mr. Scrooge's signature can be represented as a polyline A1A2... An. Scrooge signs like that: first it places a pen at the point A1, then draws a segment from point A1 to point A2, then he draws a segment from point A2 to point A3 and so on to point An, where he stops signing and takes the pen off the paper. At that the resulting line can intersect with itself and partially repeat itself but Scrooge pays no attention to it and never changes his signing style. As Scrooge makes the signature, he never takes the pen off the paper and his writing speed is constant — 50 millimeters per second.Scrooge signed exactly k papers throughout his life and all those signatures look the same.Find the total time Scrooge wasted signing the papers.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"967"You are given a complete directed graph $$$K_n$$$ with $$$n$$$ vertices: each pair of vertices $$$u \neq v$$$ in $$$K_n$$$ have both directed edges $$$(u, v)$$$ and $$$(v, u)$$$; there are no self-loops.You should find such a cycle in $$$K_n$$$ that visits every directed edge exactly once (allowing for revisiting vertices).We can write such cycle as a list of $$$n(n - 1) + 1$$$ vertices $$$v_1, v_2, v_3, \dots, v_{n(n - 1) - 1}, v_{n(n - 1)}, v_{n(n - 1) + 1} = v_1$$$ — a visiting order, where each $$$(v_i, v_{i + 1})$$$ occurs exactly once.Find the lexicographically smallest such cycle. It's not hard to prove that the cycle always exists.Since the answer can be too large print its $$$[l, r]$$$ segment, in other words, $$$v_l, v_{l + 1}, \dots, v_r$$$.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"968"You are given a positive integer $$$n$$$. In one move, you can increase $$$n$$$ by one (i.e. make $$$n := n + 1$$$). Your task is to find the minimum number of moves you need to perform in order to make the sum of digits of $$$n$$$ be less than or equal to $$$s$$$.You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"969"In Disgaea as in most role-playing games, characters have skills that determine the character's ability to use certain weapons or spells. If the character does not have the necessary skill, he cannot use it. The skill level is represented as an integer that increases when you use this skill. Different character classes are characterized by different skills. Unfortunately, the skills that are uncommon for the given character's class are quite difficult to obtain. To avoid this limitation, there is the so-called transmigration. Transmigration is reincarnation of the character in a new creature. His soul shifts to a new body and retains part of his experience from the previous life. As a result of transmigration the new character gets all the skills of the old character and the skill levels are reduced according to the k coefficient (if the skill level was equal to x, then after transmigration it becomes equal to [kx], where [y] is the integral part of y). If some skill's levels are strictly less than 100, these skills are forgotten (the character does not have them any more). After that the new character also gains the skills that are specific for his class, but are new to him. The levels of those additional skills are set to 0. Thus, one can create a character with skills specific for completely different character classes via transmigrations. For example, creating a mage archer or a thief warrior is possible. You are suggested to solve the following problem: what skills will the character have after transmigration and what will the levels of those skills be?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"970"One day Polycarp decided to rewatch his absolute favourite episode of well-known TV series ""Tufurama"". He was pretty surprised when he got results only for season 7 episode 3 with his search query of ""Watch Tufurama season 3 episode 7 online full hd free"". This got Polycarp confused — what if he decides to rewatch the entire series someday and won't be able to find the right episodes to watch? Polycarp now wants to count the number of times he will be forced to search for an episode using some different method.TV series have n seasons (numbered 1 through n), the i-th season has ai episodes (numbered 1 through ai). Polycarp thinks that if for some pair of integers x and y (x < y) exist both season x episode y and season y episode x then one of these search queries will include the wrong results. Help Polycarp to calculate the number of such pairs!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"971"You have a description of a lever as string s. We'll represent the string length as record |s|, then the lever looks as a horizontal bar with weights of length |s| - 1 with exactly one pivot. We will assume that the bar is a segment on the Ox axis between points 0 and |s| - 1.The decoding of the lever description is given below.  If the i-th character of the string equals ""^"", that means that at coordinate i there is the pivot under the bar.  If the i-th character of the string equals ""="", that means that at coordinate i there is nothing lying on the bar.  If the i-th character of the string equals digit c (1-9), that means that at coordinate i there is a weight of mass c on the bar. Your task is, given the lever description, print if it will be in balance or not. Assume that the bar doesn't weight anything. Assume that the bar initially is in balance then all weights are simultaneously put on it. After that the bar either tilts to the left, or tilts to the right, or is in balance.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"972"You are given an array $$$a_1, a_2, \dots, a_n$$$ of integer numbers.Your task is to divide the array into the maximum number of segments in such a way that:  each element is contained in exactly one segment;  each segment contains at least one element;  there doesn't exist a non-empty subset of segments such that bitwise XOR of the numbers from them is equal to $$$0$$$. Print the maximum number of segments the array can be divided into. Print -1 if no suitable division exists.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"973"An array is called beautiful if all the elements in the array are equal.You can transform an array using the following steps any number of times:   Choose two indices $$$i$$$ and $$$j$$$ ($$$1 \leq i,j \leq n$$$), and an integer $$$x$$$ ($$$1 \leq x \leq a_i$$$). Let $$$i$$$ be the source index and $$$j$$$ be the sink index.  Decrease the $$$i$$$-th element by $$$x$$$, and increase the $$$j$$$-th element by $$$x$$$. The resulting values at $$$i$$$-th and $$$j$$$-th index are $$$a_i-x$$$ and $$$a_j+x$$$ respectively.  The cost of this operation is $$$x \cdot |j-i| $$$.  Now the $$$i$$$-th index can no longer be the sink and the $$$j$$$-th index can no longer be the source.  The total cost of a transformation is the sum of all the costs in step $$$3$$$.For example, array $$$[0, 2, 3, 3]$$$ can be transformed into a beautiful array $$$[2, 2, 2, 2]$$$ with total cost $$$1 \cdot |1-3| + 1 \cdot |1-4| = 5$$$.An array is called balanced, if it can be transformed into a beautiful array, and the cost of such transformation is uniquely defined. In other words, the minimum cost of transformation into a beautiful array equals the maximum cost.You are given an array $$$a_1, a_2, \ldots, a_n$$$ of length $$$n$$$, consisting of non-negative integers. Your task is to find the number of balanced arrays which are permutations of the given array. Two arrays are considered different, if elements at some position differ. Since the answer can be large, output it modulo $$$10^9 + 7$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"974"The Beroil corporation structure is hierarchical, that is it can be represented as a tree. Let's examine the presentation of this structure as follows:  employee ::= name. | name:employee1,employee2, ... ,employeek.  name ::= name of an employee That is, the description of each employee consists of his name, a colon (:), the descriptions of all his subordinates separated by commas, and, finally, a dot. If an employee has no subordinates, then the colon is not present in his description.For example, line MIKE:MAX.,ARTEM:MIKE..,DMITRY:DMITRY.,DMITRY... is the correct way of recording the structure of a corporation where the director MIKE has subordinates MAX, ARTEM and DMITRY. ARTEM has a subordinate whose name is MIKE, just as the name of his boss and two subordinates of DMITRY are called DMITRY, just like himself.In the Beroil corporation every employee can only correspond with his subordinates, at that the subordinates are not necessarily direct. Let's call an uncomfortable situation the situation when a person whose name is s writes a letter to another person whose name is also s. In the example given above are two such pairs: a pair involving MIKE, and two pairs for DMITRY (a pair for each of his subordinates).Your task is by the given structure of the corporation to find the number of uncomfortable pairs in it.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"975"Nian is a monster which lives deep in the oceans. Once a year, it shows up on the land, devouring livestock and even people. In order to keep the monster away, people fill their villages with red colour, light, and cracking noise, all of which frighten the monster out of coming.Little Tommy has n lanterns and Big Banban has m lanterns. Tommy's lanterns have brightness a1, a2, ..., an, and Banban's have brightness b1, b2, ..., bm respectively.Tommy intends to hide one of his lanterns, then Banban picks one of Tommy's non-hidden lanterns and one of his own lanterns to form a pair. The pair's brightness will be the product of the brightness of two lanterns.Tommy wants to make the product as small as possible, while Banban tries to make it as large as possible.You are asked to find the brightness of the chosen pair if both of them choose optimally.",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"976"Guy-Manuel and Thomas are going to build a polygon spaceship. You're given a strictly convex (i. e. no three points are collinear) polygon $$$P$$$ which is defined by coordinates of its vertices. Define $$$P(x,y)$$$ as a polygon obtained by translating $$$P$$$ by vector $$$\overrightarrow {(x,y)}$$$. The picture below depicts an example of the translation:Define $$$T$$$ as a set of points which is the union of all $$$P(x,y)$$$ such that the origin $$$(0,0)$$$ lies in $$$P(x,y)$$$ (both strictly inside and on the boundary). There is also an equivalent definition: a point $$$(x,y)$$$ lies in $$$T$$$ only if there are two points $$$A,B$$$ in $$$P$$$ such that $$$\overrightarrow {AB} = \overrightarrow {(x,y)}$$$. One can prove $$$T$$$ is a polygon too. For example, if $$$P$$$ is a regular triangle then $$$T$$$ is a regular hexagon. At the picture below $$$P$$$ is drawn in black and some $$$P(x,y)$$$ which contain the origin are drawn in colored: The spaceship has the best aerodynamic performance if $$$P$$$ and $$$T$$$ are similar. Your task is to check whether the polygons $$$P$$$ and $$$T$$$ are similar.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"977"Anton's favourite geometric figures are regular polyhedrons. Note that there are five kinds of regular polyhedrons:   Tetrahedron. Tetrahedron has 4 triangular faces.  Cube. Cube has 6 square faces.  Octahedron. Octahedron has 8 triangular faces.  Dodecahedron. Dodecahedron has 12 pentagonal faces.  Icosahedron. Icosahedron has 20 triangular faces. All five kinds of polyhedrons are shown on the picture below:  Anton has a collection of n polyhedrons. One day he decided to know, how many faces his polyhedrons have in total. Help Anton and find this number!",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"978"You have a tree of $$$n$$$ vertices. You are going to convert this tree into $$$n$$$ rubber bands on infinitely large plane. Conversion rule follows:  For every pair of vertices $$$a$$$ and $$$b$$$, rubber bands $$$a$$$ and $$$b$$$ should intersect if and only if there is an edge exists between $$$a$$$ and $$$b$$$ in the tree.  Shape of rubber bands must be a simple loop. In other words, rubber band is a loop which doesn't self-intersect. Now let's define following things:   Rubber band $$$a$$$ includes rubber band $$$b$$$, if and only if rubber band $$$b$$$ is in rubber band $$$a$$$'s area, and they don't intersect each other.  Sequence of rubber bands $$$a_{1}, a_{2}, \ldots, a_{k}$$$ ($$$k \ge 2$$$) are nested, if and only if for all $$$i$$$ ($$$2 \le i \le k$$$), $$$a_{i-1}$$$ includes $$$a_{i}$$$.   This is an example of conversion. Note that rubber bands $$$5$$$ and $$$6$$$ are nested. It can be proved that is it possible to make a conversion and sequence of nested rubber bands under given constraints.What is the maximum length of sequence of nested rubber bands can be obtained from given tree? Find and print it.","['math', 'trees']","[0, 0, 0, 1, 0, 0, 0, 1]"979"A long time ago in some far country lived king Copa. After the recent king's reform, he got so large powers that started to keep the books by himself.The total income A of his kingdom during 0-th year is known, as well as the total income B during n-th year (these numbers can be negative — it means that there was a loss in the correspondent year). King wants to show financial stability. To do this, he needs to find common coefficient X — the coefficient of income growth during one year. This coefficient should satisfy the equation:A·Xn = B.Surely, the king is not going to do this job by himself, and demands you to find such number X.It is necessary to point out that the fractional numbers are not used in kingdom's economy. That's why all input numbers as well as coefficient X must be integers. The number X may be zero or negative.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"980"Andrewid the Android is a galaxy-famous detective. He is now investigating the case of vandalism at the exhibition of contemporary art.The main exhibit is a construction of n matryoshka dolls that can be nested one into another. The matryoshka dolls are numbered from 1 to n. A matryoshka with a smaller number can be nested in a matryoshka with a higher number, two matryoshkas can not be directly nested in the same doll, but there may be chain nestings, for example, 1 → 2 → 4 → 5. In one second, you can perform one of the two following operations:  Having a matryoshka a that isn't nested in any other matryoshka and a matryoshka b, such that b doesn't contain any other matryoshka and is not nested in any other matryoshka, you may put a in b;  Having a matryoshka a directly contained in matryoshka b, such that b is not nested in any other matryoshka, you may get a out of b. According to the modern aesthetic norms the matryoshka dolls on display were assembled in a specific configuration, i.e. as several separate chains of nested matryoshkas, but the criminal, following the mysterious plan, took out all the dolls and assembled them into a single large chain (1 → 2 → ... → n). In order to continue the investigation Andrewid needs to know in what minimum time it is possible to perform this action.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"981"For the given integer $$$n$$$ ($$$n > 2$$$) let's write down all the strings of length $$$n$$$ which contain $$$n-2$$$ letters 'a' and two letters 'b' in lexicographical (alphabetical) order.Recall that the string $$$s$$$ of length $$$n$$$ is lexicographically less than string $$$t$$$ of length $$$n$$$, if there exists such $$$i$$$ ($$$1 \le i \le n$$$), that $$$s_i < t_i$$$, and for any $$$j$$$ ($$$1 \le j < i$$$) $$$s_j = t_j$$$. The lexicographic comparison of strings is implemented by the operator < in modern programming languages.For example, if $$$n=5$$$ the strings are (the order does matter):  aaabb  aabab  aabba  abaab  ababa  abbaa  baaab  baaba  babaa  bbaaa It is easy to show that such a list of strings will contain exactly $$$\frac{n \cdot (n-1)}{2}$$$ strings.You are given $$$n$$$ ($$$n > 2$$$) and $$$k$$$ ($$$1 \le k \le \frac{n \cdot (n-1)}{2}$$$). Print the $$$k$$$-th string from the list.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"982You are given n points on a line with their coordinates xi. Find the point x so the sum of distances to the given points is minimal.,[],"[0, 0, 0, 0, 0, 0, 0, 0]"983"Vanya is managed to enter his favourite site Codehorses. Vanya uses n distinct passwords for sites at all, however he can't remember which one exactly he specified during Codehorses registration.Vanya will enter passwords in order of non-decreasing their lengths, and he will enter passwords of same length in arbitrary order. Just when Vanya will have entered the correct password, he is immediately authorized on the site. Vanya will not enter any password twice.Entering any passwords takes one second for Vanya. But if Vanya will enter wrong password k times, then he is able to make the next try only 5 seconds after that. Vanya makes each try immediately, that is, at each moment when Vanya is able to enter password, he is doing that.Determine how many seconds will Vanya need to enter Codehorses in the best case for him (if he spends minimum possible number of second) and in the worst case (if he spends maximum possible amount of seconds).","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"984"There are $$$n$$$ pillars aligned in a row and numbered from $$$1$$$ to $$$n$$$.Initially each pillar contains exactly one disk. The $$$i$$$-th pillar contains a disk having radius $$$a_i$$$.You can move these disks from one pillar to another. You can take a disk from pillar $$$i$$$ and place it on top of pillar $$$j$$$ if all these conditions are met:  there is no other pillar between pillars $$$i$$$ and $$$j$$$. Formally, it means that $$$|i - j| = 1$$$;  pillar $$$i$$$ contains exactly one disk;  either pillar $$$j$$$ contains no disks, or the topmost disk on pillar $$$j$$$ has radius strictly greater than the radius of the disk you move. When you place a disk on a pillar that already has some disks on it, you put the new disk on top of previously placed disks, so the new disk will be used to check the third condition if you try to place another disk on the same pillar.You may take any disk and place it on other pillar any number of times, provided that every time you do it, all three aforementioned conditions are met. Now you wonder, is it possible to place all $$$n$$$ disks on the same pillar simultaneously?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"985"There are $$$n$$$ piles of stones, where the $$$i$$$-th pile has $$$a_i$$$ stones. Two people play a game, where they take alternating turns removing stones.In a move, a player may remove a positive number of stones from the first non-empty pile (the pile with the minimal index, that has at least one stone). The first player who cannot make a move (because all piles are empty) loses the game. If both players play optimally, determine the winner of the game.",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"986"Jeel and Ashish play a game on an $$$n \times m$$$ matrix. The rows are numbered $$$1$$$ to $$$n$$$ from top to bottom and the columns are numbered $$$1$$$ to $$$m$$$ from left to right. They play turn by turn. Ashish goes first.Initially, each cell of the matrix contains a non-negative integer. Each turn, a player must perform all of the following actions in order.   Choose a starting cell $$$(r_1, c_1)$$$ with non-zero value.  Choose a finishing cell $$$(r_2, c_2)$$$ such that $$$r_1 \leq r_2$$$ and $$$c_1 \leq c_2$$$.  Decrease the value of the starting cell by some positive non-zero integer.  Pick any of the shortest paths between the two cells and either increase, decrease or leave the values of cells on this path unchanged. Note that:   a shortest path is one that passes through the least number of cells;  all cells on this path excluding the starting cell, but the finishing cell may be modified;  the resulting value of each cell must be a non-negative integer;  the cells are modified independently and not necessarily by the same value.  If the starting and ending cells are the same, then as per the rules, the value of the cell is decreased. No other operations are performed.The game ends when all the values become zero. The player who is unable to make a move loses. It can be shown that the game will end in a finite number of moves if both players play optimally.Given the initial matrix, if both players play optimally, can you predict who will win?",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"987"Given two integers $$$n$$$ and $$$x$$$, construct an array that satisfies the following conditions:   for any element $$$a_i$$$ in the array, $$$1 \le a_i<2^n$$$;  there is no non-empty subsegment with bitwise XOR equal to $$$0$$$ or $$$x$$$,  its length $$$l$$$ should be maximized. A sequence $$$b$$$ is a subsegment of a sequence $$$a$$$ if $$$b$$$ can be obtained from $$$a$$$ by deletion of several (possibly, zero or all) elements from the beginning and several (possibly, zero or all) elements from the end.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"988"This problem is a little bit unusual. Here you are to implement an interaction with a testing system. That means that you can make queries and get responses in the online mode. Please be sure to use the stream flushing operation after each query's output in order not to leave part of your output in some buffer. For example, in C++ you've got to use the fflush(stdout) function, in Java — call System.out.flush(), and in Pascal — flush(output).Bulls and Cows (also known as Cows and Bulls or Pigs and Bulls or Bulls and Cleots) is an old code-breaking paper and pencil game for two players, predating the similar commercially marketed board game Mastermind.On a sheet of paper, the first player thinks a secret string. This string consists only of digits and has the length 4. The digits in the string must be all different, no two or more equal digits are allowed.Then the second player tries to guess his opponent's string. For every guess the first player gives the number of matches. If the matching digits are on their right positions, they are ""bulls"", if on different positions, they are ""cows"". Thus a response is a pair of numbers — the number of ""bulls"" and the number of ""cows"". A try can contain equal digits.More formally, let's the secret string is s and the second player are trying to guess it with a string x. The number of ""bulls"" is a number of such positions i (1 ≤ i ≤ 4) where s[i] = x[i]. The number of ""cows"" is a number of such digits c that s contains c in the position i (i.e. s[i] = c), x contains c, but x[i] ≠ c.For example, the secret string is ""0427"", the opponent's try is ""0724"", then the answer is 2 bulls and 2 cows (the bulls are ""0"" and ""2"", the cows are ""4"" and ""7""). If the secret string is ""0123"", the opponent's try is ""0330"", then the answer is 1 bull and 1 cow.In this problem you are to guess the string s that the system has chosen. You only know that the chosen string consists of 4 distinct digits.You can make queries to the testing system, each query is the output of a single 4-digit string. The answer to the query is the number of bulls and number of cows. If the system's response equals ""4 0"", that means the interaction with your problem is over and the program must terminate. That is possible for two reasons — the program either guessed the number x or made an invalid action (for example, printed letters instead of digits).Your program is allowed to do at most 50 queries.You can hack solutions of other participants providing a 4-digit string containing distinct digits — the secret string.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"989"Consider a hallway, which can be represented as the matrix with $$$2$$$ rows and $$$n$$$ columns. Let's denote the cell on the intersection of the $$$i$$$-th row and the $$$j$$$-th column as $$$(i, j)$$$. The distance between the cells $$$(i_1, j_1)$$$ and $$$(i_2, j_2)$$$ is $$$|i_1 - i_2| + |j_1 - j_2|$$$.There is a cleaning robot in the cell $$$(1, 1)$$$. Some cells of the hallway are clean, other cells are dirty (the cell with the robot is clean). You want to clean the hallway, so you are going to launch the robot to do this.After the robot is launched, it works as follows. While at least one cell is dirty, the robot chooses the closest (to its current cell) cell among those which are dirty, moves there and cleans it (so the cell is no longer dirty). After cleaning a cell, the robot again finds the closest dirty cell to its current cell, and so on. This process repeats until the whole hallway is clean.However, there is a critical bug in the robot's program. If at some moment, there are multiple closest (to the robot's current position) dirty cells, the robot malfunctions.You want to clean the hallway in such a way that the robot doesn't malfunction. Before launching the robot, you can clean some (possibly zero) of the dirty cells yourself. However, you don't want to do too much dirty work yourself while you have this nice, smart (yet buggy) robot to do this. Note that you cannot make a clean cell dirty.Calculate the maximum possible number of cells you can leave dirty before launching the robot, so that it doesn't malfunction.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"990"The robot is located on a checkered rectangular board of size $$$n \times m$$$ ($$$n$$$ rows, $$$m$$$ columns). The rows in the board are numbered from $$$1$$$ to $$$n$$$ from top to bottom, and the columns — from $$$1$$$ to $$$m$$$ from left to right.The robot is able to move from the current cell to one of the four cells adjacent by side.Each cell has one of the symbols 'L', 'R', 'D' or 'U' written on it, indicating the direction in which the robot will move when it gets in that cell — left, right, down or up, respectively.The robot can start its movement in any cell. He then moves to the adjacent square in the direction indicated on the current square in one move.   If the robot moves beyond the edge of the board, it falls and breaks.  If the robot appears in the cell it already visited before, it breaks (it stops and doesn't move anymore). Robot can choose any cell as the starting cell. Its goal is to make the maximum number of steps before it breaks or stops.Determine from which square the robot should start its movement in order to execute as many commands as possible. A command is considered successfully completed if the robot has moved from the square on which that command was written (it does not matter whether to another square or beyond the edge of the board).",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"991"Polar bears like unique arrays — that is, arrays without repeated elements. You have got a unique array s with length n containing non-negative integers. Since you are good friends with Alice and Bob, you decide to split the array in two. Precisely, you need to construct two arrays a and b that are also of length n, with the following conditions for all i (1 ≤ i ≤ n):  ai, bi are non-negative integers;  si = ai + bi . Ideally, a and b should also be unique arrays. However, life in the Arctic is hard and this is not always possible. Fortunately, Alice and Bob are still happy if their arrays are almost unique. We define an array of length n to be almost unique, if and only if it can be turned into a unique array by removing no more than  entries.For example, the array [1, 2, 1, 3, 2] is almost unique because after removing the first two entries, it becomes [1, 3, 2]. The array [1, 2, 1, 3, 1, 2] is not almost unique because we need to remove at least 3 entries to turn it into a unique array.So, your task is to split the given unique array s into two almost unique arrays a and b.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"992"Stanley defines the beauty of an array $$$a$$$ of length $$$n$$$, which contains non-negative integers, as follows: $$$$$$\sum\limits_{i = 1}^{n} \left \lfloor \frac{a_{i}}{k} \right \rfloor,$$$$$$ which means that we divide each element by $$$k$$$, round it down, and sum up the resulting values.Stanley told Sam the integer $$$k$$$ and asked him to find an array $$$a$$$ of $$$n$$$ non-negative integers, such that the beauty is equal to $$$b$$$ and the sum of elements is equal to $$$s$$$. Help Sam — find any of the arrays satisfying the conditions above.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"993"Kirito is stuck on a level of the MMORPG he is playing now. To move on in the game, he's got to defeat all n dragons that live on this level. Kirito and the dragons have strength, which is represented by an integer. In the duel between two opponents the duel's outcome is determined by their strength. Initially, Kirito's strength equals s.If Kirito starts duelling with the i-th (1 ≤ i ≤ n) dragon and Kirito's strength is not greater than the dragon's strength xi, then Kirito loses the duel and dies. But if Kirito's strength is greater than the dragon's strength, then he defeats the dragon and gets a bonus strength increase by yi.Kirito can fight the dragons in any order. Determine whether he can move on to the next level of the game, that is, defeat all dragons without a single loss.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"994"You are at the top left cell $$$(1, 1)$$$ of an $$$n \times m$$$ labyrinth. Your goal is to get to the bottom right cell $$$(n, m)$$$. You can only move right or down, one cell per step. Moving right from a cell $$$(x, y)$$$ takes you to the cell $$$(x, y + 1)$$$, while moving down takes you to the cell $$$(x + 1, y)$$$.Some cells of the labyrinth contain rocks. When you move to a cell with rock, the rock is pushed to the next cell in the direction you're moving. If the next cell contains a rock, it gets pushed further, and so on.The labyrinth is surrounded by impenetrable walls, thus any move that would put you or any rock outside of the labyrinth is illegal.Count the number of different legal paths you can take from the start to the goal modulo $$$10^9 + 7$$$. Two paths are considered different if there is at least one cell that is visited in one path, but not visited in the other.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"995"Let's assume that we are given a matrix b of size x × y, let's determine the operation of mirroring matrix b. The mirroring of matrix b is a 2x × y matrix c which has the following properties:  the upper half of matrix c (rows with numbers from 1 to x) exactly matches b;  the lower half of matrix c (rows with numbers from x + 1 to 2x) is symmetric to the upper one; the symmetry line is the line that separates two halves (the line that goes in the middle, between rows x and x + 1). Sereja has an n × m matrix a. He wants to find such matrix b, that it can be transformed into matrix a, if we'll perform on it several (possibly zero) mirrorings. What minimum number of rows can such matrix contain?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"996"Martian scientists explore Ganymede, one of Jupiter's numerous moons. Recently, they have found ruins of an ancient civilization. The scientists brought to Mars some tablets with writings in a language unknown to science.They found out that the inhabitants of Ganymede used an alphabet consisting of two letters, and each word was exactly $$$\ell$$$ letters long. So, the scientists decided to write each word of this language as an integer from $$$0$$$ to $$$2^{\ell} - 1$$$ inclusively. The first letter of the alphabet corresponds to zero bit in this integer, and the second letter corresponds to one bit.The same word may have various forms in this language. Then, you need to restore the initial form. The process of doing it is described below.Denote the distance between two words as the amount of positions, in which these words differ. For example, the distance between $$$1001_2$$$ and $$$1100_2$$$ (in binary) is equal to two, as these words have different letters in the second and the fourth positions, counting from left to right. Further, denote the distance between words $$$x$$$ and $$$y$$$ as $$$d(x, y)$$$.Let the word have $$$n$$$ forms, the $$$i$$$-th of which is described with an integer $$$x_i$$$. All the $$$x_i$$$ are not necessarily different, as two various forms of the word can be written the same. Consider some word $$$y$$$. Then, closeness of the word $$$y$$$ is equal to the sum of distances to each of the word forms, i. e. the sum $$$d(x_i, y)$$$ over all $$$1 \le i \le n$$$.The initial form is the word $$$y$$$ with minimal possible nearness.You need to help the scientists and write the program which finds the initial form of the word given all its known forms. Note that the initial form is not necessarily equal to any of the $$$n$$$ given forms.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"997"You are given a string $$$s$$$ consisting only of lowercase Latin letters.You can rearrange all letters of this string as you wish. Your task is to obtain a good string by rearranging the letters of the given string or report that it is impossible to do it.Let's call a string good if it is not a palindrome. Palindrome is a string which is read from left to right the same as from right to left. For example, strings ""abacaba"", ""aa"" and ""z"" are palindromes and strings ""bba"", ""xd"" are not.You have to answer $$$t$$$ independent queries.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"998Given simple (without self-intersections) n-gon. It is not necessary convex. Also you are given m lines. For each line find the length of common part of the line and the n-gon.The boundary of n-gon belongs to polygon. It is possible that n-gon contains 180-degree angles.,['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"999"A positive integer $$$a$$$ is given. Baron Munchausen claims that he knows such a positive integer $$$n$$$ that if one multiplies $$$n$$$ by $$$a$$$, the sum of its digits decreases $$$a$$$ times. In other words, $$$S(an) = S(n)/a$$$, where $$$S(x)$$$ denotes the sum of digits of the number $$$x$$$. Find out if what Baron told can be true.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1000Little Artem found a grasshopper. He brought it to his house and constructed a jumping area for him.The area looks like a strip of cells 1 × n. Each cell contains the direction for the next jump and the length of that jump. Grasshopper starts in the first cell and follows the instructions written on the cells. Grasshopper stops immediately if it jumps out of the strip. Now Artem wants to find out if this will ever happen.,[],"[0, 0, 0, 0, 0, 0, 0, 0]"1001"There are n points on a straight line, and the i-th point among them is located at xi. All these coordinates are distinct.Determine the number m — the smallest number of points you should add on the line to make the distances between all neighboring points equal. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1002"Ivan recently bought a detective book. The book is so interesting that each page of this book introduces some sort of a mystery, which will be explained later. The $$$i$$$-th page contains some mystery that will be explained on page $$$a_i$$$ ($$$a_i \ge i$$$).Ivan wants to read the whole book. Each day, he reads the first page he didn't read earlier, and continues to read the following pages one by one, until all the mysteries he read about are explained and clear to him (Ivan stops if there does not exist any page $$$i$$$ such that Ivan already has read it, but hasn't read page $$$a_i$$$). After that, he closes the book and continues to read it on the following day from the next page.How many days will it take to read the whole book?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1003"Polycarp is flying in the airplane. Finally, it is his favorite time — the lunchtime. The BerAvia company stewardess is giving food consecutively to all the passengers from the 1-th one to the last one. Polycarp is sitting on seat m, that means, he will be the m-th person to get food.The flight menu has k dishes in total and when Polycarp boarded the flight, he had time to count the number of portions of each dish on board. Thus, he knows values a1, a2, ..., ak, where ai is the number of portions of the i-th dish.The stewardess has already given food to m - 1 passengers, gave Polycarp a polite smile and asked him what he would prefer. That's when Polycarp realized that they might have run out of some dishes by that moment. For some of the m - 1 passengers ahead of him, he noticed what dishes they were given. Besides, he's heard some strange mumbling from some of the m - 1 passengers ahead of him, similar to phrase 'I'm disappointed'. That happened when a passenger asked for some dish but the stewardess gave him a polite smile and said that they had run out of that dish. In that case the passenger needed to choose some other dish that was available. If Polycarp heard no more sounds from a passenger, that meant that the passenger chose his dish at the first try.Help Polycarp to find out for each dish: whether they could have run out of the dish by the moment Polyarp was served or that dish was definitely available.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1004"Sasha likes programming. Once, during a very long contest, Sasha decided that he was a bit tired and needed to relax. So he did. But since Sasha isn't an ordinary guy, he prefers to relax unusually. During leisure time Sasha likes to upsolve unsolved problems because upsolving is very useful.Therefore, Sasha decided to upsolve the following problem:You have an array $$$a$$$ with $$$n$$$ integers. You need to count the number of funny pairs $$$(l, r)$$$ $$$(l \leq r)$$$. To check if a pair $$$(l, r)$$$ is a funny pair, take $$$mid = \frac{l + r - 1}{2}$$$, then if $$$r - l + 1$$$ is an even number and $$$a_l \oplus a_{l+1} \oplus \ldots \oplus a_{mid} = a_{mid + 1} \oplus a_{mid + 2} \oplus \ldots \oplus a_r$$$, then the pair is funny. In other words, $$$\oplus$$$ of elements of the left half of the subarray from $$$l$$$ to $$$r$$$ should be equal to $$$\oplus$$$ of elements of the right half. Note that $$$\oplus$$$ denotes the bitwise XOR operation.It is time to continue solving the contest, so Sasha asked you to solve this task.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1005"A line on the plane is described by an equation Ax + By + C = 0. You are to find any point on this line, whose coordinates are integer numbers from  - 5·1018 to 5·1018 inclusive, or to find out that such points do not exist.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1006"There are one cat, $$$k$$$ mice, and one hole on a coordinate line. The cat is located at the point $$$0$$$, the hole is located at the point $$$n$$$. All mice are located between the cat and the hole: the $$$i$$$-th mouse is located at the point $$$x_i$$$ ($$$0 < x_i < n$$$). At each point, many mice can be located.In one second, the following happens. First, exactly one mouse moves to the right by $$$1$$$. If the mouse reaches the hole, it hides (i.e. the mouse will not any more move to any point and will not be eaten by the cat). Then (after that the mouse has finished its move) the cat moves to the right by $$$1$$$. If at the new cat's position, some mice are located, the cat eats them (they will not be able to move after that). The actions are performed until any mouse hasn't been hidden or isn't eaten.In other words, the first move is made by a mouse. If the mouse has reached the hole, it's saved. Then the cat makes a move. The cat eats the mice located at the pointed the cat has reached (if the cat has reached the hole, it eats nobody).Each second, you can select a mouse that will make a move. What is the maximum number of mice that can reach the hole without being eaten?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1007"This is an interactive problem.Vasya and Vitya play a game. Vasya thought of two integers $$$a$$$ and $$$b$$$ from $$$1$$$ to $$$n$$$ and Vitya tries to guess them. Each round he tells Vasya two numbers $$$x$$$ and $$$y$$$ from $$$1$$$ to $$$n$$$. If both $$$x=a$$$ and $$$y=b$$$ then Vitya wins. Else Vasya must say one of the three phrases:   $$$x$$$ is less than $$$a$$$;  $$$y$$$ is less than $$$b$$$;  $$$x$$$ is greater than $$$a$$$ or $$$y$$$ is greater than $$$b$$$. Vasya can't lie, but if multiple phrases are true, he may choose any of them. For example, if Vasya thought of numbers $$$2$$$ and $$$4$$$, then he answers with the phrase $$$3$$$ to a query $$$(3, 4)$$$, and he can answer with the phrase $$$1$$$ or phrase $$$3$$$ to a query $$$(1, 5)$$$.Help Vitya win in no more than $$$600$$$ rounds. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1008"You are given a string $$$s$$$, consisting of lowercase Latin letters. Every letter appears in it no more than twice.Your task is to rearrange the letters in the string in such a way that for each pair of letters that appear exactly twice, the distance between the letters in the pair is the same. You are not allowed to add or remove letters.It can be shown that the answer always exists. If there are multiple answers, print any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1009"The cities of Byteland and Berland are located on the axis $$$Ox$$$. In addition, on this axis there are also disputed cities, which belong to each of the countries in their opinion. Thus, on the line $$$Ox$$$ there are three types of cities:  the cities of Byteland,  the cities of Berland,  disputed cities. Recently, the project BNET has been launched — a computer network of a new generation. Now the task of the both countries is to connect the cities so that the network of this country is connected.The countries agreed to connect the pairs of cities with BNET cables in such a way that:  If you look at the only cities of Byteland and the disputed cities, then in the resulting set of cities, any city should be reachable from any other one by one or more cables,  If you look at the only cities of Berland and the disputed cities, then in the resulting set of cities, any city should be reachable from any other one by one or more cables. Thus, it is necessary to choose a set of pairs of cities to connect by cables in such a way that both conditions are satisfied simultaneously. Cables allow bi-directional data transfer. Each cable connects exactly two distinct cities.The cost of laying a cable from one city to another is equal to the distance between them. Find the minimum total cost of laying a set of cables so that two subsets of cities (Byteland and disputed cities, Berland and disputed cities) are connected.Each city is a point on the line $$$Ox$$$. It is technically possible to connect the cities $$$a$$$ and $$$b$$$ with a cable so that the city $$$c$$$ ($$$a < c < b$$$) is not connected to this cable, where $$$a$$$, $$$b$$$ and $$$c$$$ are simultaneously coordinates of the cities $$$a$$$, $$$b$$$ and $$$c$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1010"Chaneka has a hobby of playing with animal toys. Every toy has a different fun value, a real number. Chaneka has four boxes to store the toys with specification:   The first box stores toys with fun values in range of $$$(-\infty,-1]$$$.  The second box stores toys with fun values in range of $$$(-1, 0)$$$.  The third box stores toys with fun values in range of $$$(0, 1)$$$.  The fourth box stores toys with fun value in range of $$$[1, \infty)$$$. Chaneka has $$$A$$$, $$$B$$$, $$$C$$$, $$$D$$$ toys in the first, second, third, and fourth box, respectively. One day she decides that she only wants one toy, a super toy. So she begins to create this super toy by sewing all the toys she has.While the number of toys Chaneka has is more than 1, she takes two different toys randomly and then sews them together, creating a new toy. The fun value of this new toy is equal to the multiplication of fun values of the sewn toys. She then puts this new toy in the appropriate box. She repeats this process until she only has one toy. This last toy is the super toy, and the box that stores this toy is the special box.As an observer, you only know the number of toys in each box initially but do not know their fun values. You also don't see the sequence of Chaneka's sewing. Determine which boxes can be the special box after Chaneka found her super toy.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1011"Polycarp had an array $$$a$$$ of $$$3$$$ positive integers. He wrote out the sums of all non-empty subsequences of this array, sorted them in non-decreasing order, and got an array $$$b$$$ of $$$7$$$ integers.For example, if $$$a = \{1, 4, 3\}$$$, then Polycarp wrote out $$$1$$$, $$$4$$$, $$$3$$$, $$$1 + 4 = 5$$$, $$$1 + 3 = 4$$$, $$$4 + 3 = 7$$$, $$$1 + 4 + 3 = 8$$$. After sorting, he got an array $$$b = \{1, 3, 4, 4, 5, 7, 8\}.$$$Unfortunately, Polycarp lost the array $$$a$$$. He only has the array $$$b$$$ left. Help him to restore the array $$$a$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1012"Each item in the game has a level. The higher the level is, the higher basic parameters the item has. We shall consider only the following basic parameters: attack (atk), defense (def) and resistance to different types of impact (res).Each item belongs to one class. In this problem we will only consider three of such classes: weapon, armor, orb.Besides, there's a whole new world hidden inside each item. We can increase an item's level travelling to its world. We can also capture the so-called residents in the Item WorldResidents are the creatures that live inside items. Each resident gives some bonus to the item in which it is currently located. We will only consider residents of types: gladiator (who improves the item's atk), sentry (who improves def) and physician (who improves res).Each item has the size parameter. The parameter limits the maximum number of residents that can live inside an item. We can move residents between items. Within one moment of time we can take some resident from an item and move it to some other item if it has a free place for a new resident. We cannot remove a resident from the items and leave outside — any of them should be inside of some item at any moment of time.Laharl has a certain number of items. He wants to move the residents between items so as to equip himself with weapon, armor and a defensive orb. The weapon's atk should be largest possible in the end. Among all equipping patterns containing weapon's maximum atk parameter we should choose the ones where the armor’s def parameter is the largest possible. Among all such equipment patterns we should choose the one where the defensive orb would have the largest possible res parameter. Values of the parameters def and res of weapon, atk and res of armor and atk and def of orb are indifferent for Laharl.Find the optimal equipment pattern Laharl can get.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1013"You are on the island which can be represented as a $$$n \times m$$$ table. The rows are numbered from $$$1$$$ to $$$n$$$ and the columns are numbered from $$$1$$$ to $$$m$$$. There are $$$k$$$ treasures on the island, the $$$i$$$-th of them is located at the position $$$(r_i, c_i)$$$.Initially you stand at the lower left corner of the island, at the position $$$(1, 1)$$$. If at any moment you are at the cell with a treasure, you can pick it up without any extra time. In one move you can move up (from $$$(r, c)$$$ to $$$(r+1, c)$$$), left (from $$$(r, c)$$$ to $$$(r, c-1)$$$), or right (from position $$$(r, c)$$$ to $$$(r, c+1)$$$). Because of the traps, you can't move down.However, moving up is also risky. You can move up only if you are in a safe column. There are $$$q$$$ safe columns: $$$b_1, b_2, \ldots, b_q$$$. You want to collect all the treasures as fast as possible. Count the minimum number of moves required to collect all the treasures.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1014"You are given an array of n integer numbers. Let sum(l, r) be the sum of all numbers on positions from l to r non-inclusive (l-th element is counted, r-th element is not counted). For indices l and r holds 0 ≤ l ≤ r ≤ n. Indices in array are numbered from 0. For example, if a = [ - 5, 3, 9, 4], then sum(0, 1) =  - 5, sum(0, 2) =  - 2, sum(1, 4) = 16 and sum(i, i) = 0 for each i from 0 to 4.Choose the indices of three delimiters delim0, delim1, delim2 (0 ≤ delim0 ≤ delim1 ≤ delim2 ≤ n) and divide the array in such a way that the value of res = sum(0, delim0) - sum(delim0, delim1) + sum(delim1, delim2) - sum(delim2, n) is maximal. Note that some of the expressions sum(l, r) can correspond to empty segments (if l = r for some segment).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1015"You are given a sequence of $$$n$$$ integers $$$a_1, a_2, \ldots, a_n$$$.You have to construct two sequences of integers $$$b$$$ and $$$c$$$ with length $$$n$$$ that satisfy:  for every $$$i$$$ ($$$1\leq i\leq n$$$) $$$b_i+c_i=a_i$$$  $$$b$$$ is non-decreasing, which means that for every $$$1<i\leq n$$$, $$$b_i\geq b_{i-1}$$$ must hold  $$$c$$$ is non-increasing, which means that for every $$$1<i\leq n$$$, $$$c_i\leq c_{i-1}$$$ must hold You have to minimize $$$\max(b_i,c_i)$$$. In other words, you have to minimize the maximum number in sequences $$$b$$$ and $$$c$$$.Also there will be $$$q$$$ changes, the $$$i$$$-th change is described by three integers $$$l,r,x$$$. You should add $$$x$$$ to $$$a_l,a_{l+1}, \ldots, a_r$$$. You have to find the minimum possible value of $$$\max(b_i,c_i)$$$ for the initial sequence and for sequence after each change.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1016"You are given an array $$$a$$$ consisting of $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$. You want to split it into exactly $$$k$$$ non-empty non-intersecting subsegments such that each subsegment has odd sum (i. e. for each subsegment, the sum of all elements that belong to this subsegment is odd). It is impossible to rearrange (shuffle) the elements of a given array. Each of the $$$n$$$ elements of the array $$$a$$$ must belong to exactly one of the $$$k$$$ subsegments.Let's see some examples of dividing the array of length $$$5$$$ into $$$3$$$ subsegments (not necessarily with odd sums): $$$[1, 2, 3, 4, 5]$$$ is the initial array, then all possible ways to divide it into $$$3$$$ non-empty non-intersecting subsegments are described below:  $$$[1], [2], [3, 4, 5]$$$;  $$$[1], [2, 3], [4, 5]$$$;  $$$[1], [2, 3, 4], [5]$$$;  $$$[1, 2], [3], [4, 5]$$$;  $$$[1, 2], [3, 4], [5]$$$;  $$$[1, 2, 3], [4], [5]$$$. Of course, it can be impossible to divide the initial array into exactly $$$k$$$ subsegments in such a way that each of them will have odd sum of elements. In this case print ""NO"". Otherwise, print ""YES"" and any possible division of the array. See the output format for the detailed explanation.You have to answer $$$q$$$ independent queries.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1017"Let's consider all integers in the range from $$$1$$$ to $$$n$$$ (inclusive).Among all pairs of distinct integers in this range, find the maximum possible greatest common divisor of integers in pair. Formally, find the maximum value of $$$\mathrm{gcd}(a, b)$$$, where $$$1 \leq a < b \leq n$$$.The greatest common divisor, $$$\mathrm{gcd}(a, b)$$$, of two positive integers $$$a$$$ and $$$b$$$ is the biggest integer that is a divisor of both $$$a$$$ and $$$b$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1018"Vasya is developing his own programming language VPL (Vasya Programming Language). Right now he is busy making the system of exceptions. He thinks that the system of exceptions must function like that.The exceptions are processed by try-catch-blocks. There are two operators that work with the blocks: The try operator. It opens a new try-catch-block.  The catch(<exception_type>, <message>) operator. It closes the try-catch-block that was started last and haven't yet been closed. This block can be activated only via exception of type <exception_type>. When we activate this block, the screen displays the <message>. If at the given moment there is no open try-catch-block, then we can't use the catch operator.The exceptions can occur in the program in only one case: when we use the throw operator. The throw(<exception_type>) operator creates the exception of the given type.Let's suggest that as a result of using some throw operator the program created an exception of type a. In this case a try-catch-block is activated, such that this block's try operator was described in the program earlier than the used throw operator. Also, this block's catch operator was given an exception type a as a parameter and this block's catch operator is described later that the used throw operator. If there are several such try-catch-blocks, then the system activates the block whose catch operator occurs earlier than others. If no try-catch-block was activated, then the screen displays message ""Unhandled Exception"".To test the system, Vasya wrote a program that contains only try, catch and throw operators, one line contains no more than one operator, the whole program contains exactly one throw operator.Your task is: given a program in VPL, determine, what message will be displayed on the screen.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1019"After you had helped Fedor to find friends in the «Call of Soldiers 3» game, he stopped studying completely. Today, the English teacher told him to prepare an essay. Fedor didn't want to prepare the essay, so he asked Alex for help. Alex came to help and wrote the essay for Fedor. But Fedor didn't like the essay at all. Now Fedor is going to change the essay using the synonym dictionary of the English language.Fedor does not want to change the meaning of the essay. So the only change he would do: change a word from essay to one of its synonyms, basing on a replacement rule from the dictionary. Fedor may perform this operation any number of times.As a result, Fedor wants to get an essay which contains as little letters «R» (the case doesn't matter) as possible. If there are multiple essays with minimum number of «R»s he wants to get the one with minimum length (length of essay is the sum of the lengths of all the words in it). Help Fedor get the required essay.Please note that in this problem the case of letters doesn't matter. For example, if the synonym dictionary says that word cat can be replaced with word DOG, then it is allowed to replace the word Cat with the word doG.","['graphs', 'strings']","[0, 0, 1, 0, 0, 0, 1, 0]"1020"Bear Limak prepares problems for a programming competition. Of course, it would be unprofessional to mention the sponsor name in the statement. Limak takes it seriously and he is going to change some words. To make it still possible to read, he will try to modify each word as little as possible.Limak has a string s that consists of uppercase English letters. In one move he can swap two adjacent letters of the string. For example, he can transform a string ""ABBC"" into ""BABC"" or ""ABCB"" in one move.Limak wants to obtain a string without a substring ""VK"" (i.e. there should be no letter 'V' immediately followed by letter 'K'). It can be easily proved that it's possible for any initial string s.What is the minimum possible number of moves Limak can do?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1021"Dark Assembly is a governing body in the Netherworld. Here sit the senators who take the most important decisions for the player. For example, to expand the range of the shop or to improve certain characteristics of the character the Dark Assembly's approval is needed.The Dark Assembly consists of n senators. Each of them is characterized by his level and loyalty to the player. The level is a positive integer which reflects a senator's strength. Loyalty is the probability of a positive decision in the voting, which is measured as a percentage with precision of up to 10%. Senators make decisions by voting. Each of them makes a positive or negative decision in accordance with their loyalty. If strictly more than half of the senators take a positive decision, the player's proposal is approved. If the player's proposal is not approved after the voting, then the player may appeal against the decision of the Dark Assembly. To do that, player needs to kill all the senators that voted against (there's nothing wrong in killing senators, they will resurrect later and will treat the player even worse). The probability that a player will be able to kill a certain group of senators is equal to A / (A + B), where A is the sum of levels of all player's characters and B is the sum of levels of all senators in this group. If the player kills all undesired senators, then his proposal is approved.Senators are very fond of sweets. They can be bribed by giving them candies. For each received candy a senator increases his loyalty to the player by 10%. It's worth to mention that loyalty cannot exceed 100%. The player can take no more than k sweets to the courtroom. Candies should be given to the senators before the start of voting.Determine the probability that the Dark Assembly approves the player's proposal if the candies are distributed among the senators in the optimal way.",['probabilities'],"[0, 0, 0, 0, 0, 1, 0, 0]"1022"Door's family is going celebrate Famil Doors's birthday party. They love Famil Door so they are planning to make his birthday cake weird!The cake is a n × n square consisting of equal squares with side length 1. Each square is either empty or consists of a single chocolate. They bought the cake and randomly started to put the chocolates on the cake. The value of Famil Door's happiness will be equal to the number of pairs of cells with chocolates that are in the same row or in the same column of the cake. Famil Doors's family is wondering what is the amount of happiness of Famil going to be?Please, note that any pair can be counted no more than once, as two different cells can't share both the same row and the same column.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1023"You may have already known that a standard ICPC team consists of exactly three members. The perfect team however has more restrictions. A student can have some specialization: coder or mathematician. She/he can have no specialization, but can't have both at the same time.So the team is considered perfect if it includes at least one coder, at least one mathematician and it consists of exactly three members.You are a coach at a very large university and you know that $$$c$$$ of your students are coders, $$$m$$$ are mathematicians and $$$x$$$ have no specialization.What is the maximum number of full perfect teams you can distribute them into? Note that some students can be left without a team and each student can be a part of no more than one team.You are also asked to answer $$$q$$$ independent queries.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1024"You are given a sequence of $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$. You are also given $$$x$$$ integers $$$1, 2, \dots, x$$$.You are asked to insert each of the extra integers into the sequence $$$a$$$. Each integer can be inserted at the beginning of the sequence, at the end of the sequence, or between any elements of the sequence.The score of the resulting sequence $$$a'$$$ is the sum of absolute differences of adjacent elements in it $$$\left(\sum \limits_{i=1}^{n+x-1} |a'_i - a'_{i+1}|\right)$$$.What is the smallest possible score of the resulting sequence $$$a'$$$?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1025"You are given a prime number $$$n$$$, and an array of $$$n$$$ integers $$$b_1,b_2,\ldots, b_n$$$, where $$$0 \leq b_i < n$$$ for each $$$1 \le i \leq n$$$.You have to find a matrix $$$a$$$ of size $$$n \times n$$$ such that all of the following requirements hold:  $$$0 \le a_{i,j} < n$$$ for all $$$1 \le i, j \le n$$$.  $$$a_{r_1, c_1} + a_{r_2, c_2} \not\equiv a_{r_1, c_2} + a_{r_2, c_1} \pmod n$$$ for all positive integers $$$r_1$$$, $$$r_2$$$, $$$c_1$$$, and $$$c_2$$$ such that $$$1 \le r_1 < r_2 \le n$$$ and $$$1 \le c_1 < c_2 \le n$$$. $$$a_{i,i} = b_i$$$ for all $$$1 \le i \leq n$$$. Here $$$x \not \equiv y \pmod m$$$ denotes that $$$x$$$ and $$$y$$$ give different remainders when divided by $$$m$$$.If there are multiple solutions, output any. It can be shown that such a matrix always exists under the given constraints.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"1026"The problem uses a simplified TCP/IP address model, please read the statement carefully.An IP address is a 32-bit integer, represented as a group of four decimal 8-bit integers (without leading zeroes), separated by commas. For example, record 0.255.1.123 shows a correct IP address and records 0.256.1.123 and 0.255.1.01 do not. In the given problem an arbitrary group of four 8-bit integers is a correct IP address.Our hero Polycarpus still works as a system administrator in some large corporation. He likes beautiful IP addresses. To check if some IP address is beautiful, he should do the following:  write out in a line four 8-bit numbers of the IP address, without the commas;  check if the resulting string is a palindrome. Let us remind you that a palindrome is a string that reads the same from right to left and from left to right.For example, IP addresses 12.102.20.121 and 0.3.14.130 are beautiful (as strings ""1210220121"" and ""0314130"" are palindromes), and IP addresses 1.20.20.1 and 100.4.4.1 are not.Polycarpus wants to find all beautiful IP addresses that have the given set of digits. Each digit from the set must occur in the IP address at least once. IP address must not contain any other digits. Help him to cope with this difficult task.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1027"n people are standing in a line to play table tennis. At first, the first two players in the line play a game. Then the loser goes to the end of the line, and the winner plays with the next person from the line, and so on. They play until someone wins k games in a row. This player becomes the winner.For each of the participants, you know the power to play table tennis, and for all players these values are different. In a game the player with greater power always wins. Determine who will be the winner.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1028"There are n animals in the queue to Dr. Dolittle. When an animal comes into the office, the doctor examines him, gives prescriptions, appoints tests and may appoint extra examination. Doc knows all the forest animals perfectly well and therefore knows exactly that the animal number i in the queue will have to visit his office exactly ai times. We will assume that an examination takes much more time than making tests and other extra procedures, and therefore we will assume that once an animal leaves the room, it immediately gets to the end of the queue to the doctor. Of course, if the animal has visited the doctor as many times as necessary, then it doesn't have to stand at the end of the queue and it immediately goes home. Doctor plans to go home after receiving k animals, and therefore what the queue will look like at that moment is important for him. Since the doctor works long hours and she can't get distracted like that after all, she asked you to figure it out. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1029"You are given an array $$$a$$$ of $$$n$$$ integers. Find the number of pairs $$$(i, j)$$$ ($$$1 \le i < j \le n$$$) where the sum of $$$a_i + a_j$$$ is greater than or equal to $$$l$$$ and less than or equal to $$$r$$$ (that is, $$$l \le a_i + a_j \le r$$$).For example, if $$$n = 3$$$, $$$a = [5, 1, 2]$$$, $$$l = 4$$$ and $$$r = 7$$$, then two pairs are suitable:   $$$i=1$$$ and $$$j=2$$$ ($$$4 \le 5 + 1 \le 7$$$);  $$$i=1$$$ and $$$j=3$$$ ($$$4 \le 5 + 2 \le 7$$$). ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1030"A subsequence of length |x| of string s = s1s2... s|s| (where |s| is the length of string s) is a string x = sk1sk2... sk|x| (1 ≤ k1 < k2 < ... < k|x| ≤ |s|).You've got two strings — s and t. Let's consider all subsequences of string s, coinciding with string t. Is it true that each character of string s occurs in at least one of these subsequences? In other words, is it true that for all i (1 ≤ i ≤ |s|), there is such subsequence x = sk1sk2... sk|x| of string s, that x = t and for some j (1 ≤ j ≤ |x|) kj = i.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1031"Anton is growing a tree in his garden. In case you forgot, the tree is a connected acyclic undirected graph.There are n vertices in the tree, each of them is painted black or white. Anton doesn't like multicolored trees, so he wants to change the tree such that all vertices have the same color (black or white).To change the colors Anton can use only operations of one type. We denote it as paint(v), where v is some vertex of the tree. This operation changes the color of all vertices u such that all vertices on the shortest path from v to u have the same color (including v and u). For example, consider the tree  and apply operation paint(3) to get the following:  Anton is interested in the minimum number of operation he needs to perform in order to make the colors of all vertices equal.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"1032"Let $$$x$$$ be an array of integers $$$x = [x_1, x_2, \dots, x_n]$$$. Let's define $$$B(x)$$$ as a minimal size of a partition of $$$x$$$ into subsegments such that all elements in each subsegment are equal. For example, $$$B([3, 3, 6, 1, 6, 6, 6]) = 4$$$ using next partition: $$$[3, 3\ |\ 6\ |\ 1\ |\ 6, 6, 6]$$$.Now you don't have any exact values of $$$x$$$, but you know that $$$x_i$$$ can be any integer value from $$$[l_i, r_i]$$$ ($$$l_i \le r_i$$$) uniformly at random. All $$$x_i$$$ are independent.Calculate expected value of $$$(B(x))^2$$$, or $$$E((B(x))^2)$$$. It's guaranteed that the expected value can be represented as rational fraction $$$\frac{P}{Q}$$$ where $$$(P, Q) = 1$$$, so print the value $$$P \cdot Q^{-1} \mod 10^9 + 7$$$.","['math', 'probabilities']","[0, 0, 0, 1, 0, 1, 0, 0]"1033You have two positive integers $$$a$$$ and $$$b$$$.You can perform two kinds of operations:  $$$a = \lfloor \frac{a}{b} \rfloor$$$ (replace $$$a$$$ with the integer part of the division between $$$a$$$ and $$$b$$$)  $$$b=b+1$$$ (increase $$$b$$$ by $$$1$$$) Find the minimum number of operations required to make $$$a=0$$$.,"['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1034You are given two polynomials:  P(x) = a0·xn + a1·xn - 1 + ... + an - 1·x + an and  Q(x) = b0·xm + b1·xm - 1 + ... + bm - 1·x + bm.  Calculate limit .,['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1035"In this task, Nastya asked us to write a formal statement.An array $$$a$$$ of length $$$n$$$ and an array $$$k$$$ of length $$$n-1$$$ are given. Two types of queries should be processed:   increase $$$a_i$$$ by $$$x$$$. Then if $$$a_{i+1} < a_i + k_i$$$, $$$a_{i+1}$$$ becomes exactly $$$a_i + k_i$$$; again, if $$$a_{i+2} < a_{i+1} + k_{i+1}$$$, $$$a_{i+2}$$$ becomes exactly $$$a_{i+1} + k_{i+1}$$$, and so far for $$$a_{i+3}$$$, ..., $$$a_n$$$;  print the sum of the contiguous subarray from the $$$l$$$-th element to the $$$r$$$-th element of the array $$$a$$$. It's guaranteed that initially $$$a_i + k_i \leq a_{i+1}$$$ for all $$$1 \leq i \leq n-1$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1036"You are given two non-empty strings $$$s$$$ and $$$t$$$, consisting of Latin letters.In one move, you can choose an occurrence of the string $$$t$$$ in the string $$$s$$$ and replace it with dots.Your task is to remove all occurrences of the string $$$t$$$ in the string $$$s$$$ in the minimum number of moves, and also calculate how many different sequences of moves of the minimum length exist.Two sequences of moves are considered different if the sets of indices at which the removed occurrences of the string $$$t$$$ in $$$s$$$ begin differ. For example, the sets $$$\{1, 2, 3\}$$$ and $$$\{1, 2, 4\}$$$ are considered different, the sets $$$\{2, 4, 6\}$$$ and $$$\{2, 6\}$$$ — too, but sets $$$\{3, 5\}$$$ and $$$\{5, 3\}$$$ — not.For example, let the string $$$s =$$$ ""abababacababa"" and the string $$$t =$$$ ""aba"". We can remove all occurrences of the string $$$t$$$ in $$$2$$$ moves by cutting out the occurrences of the string $$$t$$$ at the $$$3$$$th and $$$9$$$th positions. In this case, the string $$$s$$$ is an example of the form ""ab...bac...ba"". It is also possible to cut occurrences of the string $$$t$$$ at the $$$3$$$th and $$$11$$$th positions. There are two different sequences of minimum length moves.Since the answer can be large, output it modulo $$$10^9 + 7$$$.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1037"In Berland, there is the national holiday coming — the Flag Day. In the honor of this event the president of the country decided to make a big dance party and asked your agency to organize it. He has several conditions:  overall, there must be m dances; exactly three people must take part in each dance; each dance must have one dancer in white clothes, one dancer in red clothes and one dancer in blue clothes (these are the colors of the national flag of Berland). The agency has n dancers, and their number can be less than 3m. That is, some dancers will probably have to dance in more than one dance. All of your dancers must dance on the party. However, if some dance has two or more dancers from a previous dance, then the current dance stops being spectacular. Your agency cannot allow that to happen, so each dance has at most one dancer who has danced in some previous dance. You considered all the criteria and made the plan for the m dances: each dance had three dancers participating in it. Your task is to determine the clothes color for each of the n dancers so that the President's third condition fulfilled: each dance must have a dancer in white, a dancer in red and a dancer in blue. The dancers cannot change clothes between the dances.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1038"A string is called a k-string if it can be represented as k concatenated copies of some string. For example, the string ""aabaabaabaab"" is at the same time a 1-string, a 2-string and a 4-string, but it is not a 3-string, a 5-string, or a 6-string and so on. Obviously any string is a 1-string.You are given a string s, consisting of lowercase English letters and a positive integer k. Your task is to reorder the letters in the string s in such a way that the resulting string is a k-string.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1039"Note that the only difference between the easy and hard version is the constraint on the number of queries. You can make hacks only if all versions of the problem are solved.This is an interactive problem.You are given a tree consisting of $$$n$$$ nodes numbered with integers from $$$1$$$ to $$$n$$$. Ayush and Ashish chose two secret distinct nodes in the tree. You need to find out both the nodes. You can make the following query:   Provide a list of nodes and you will receive a node from that list whose sum of distances to both the hidden nodes is minimal (if there are multiple such nodes in the list, you will receive any one of them). You will also get the sum of distances of that node to the hidden nodes. Recall that a tree is a connected graph without cycles. The distance between two nodes is defined as the number of edges in the simple path between them.More formally, let's define two hidden nodes as $$$s$$$ and $$$f$$$. In one query you can provide the set of nodes $$$\{a_1, a_2, \ldots, a_c\}$$$ of the tree. As a result, you will get two numbers $$$a_i$$$ and $$$dist(a_i, s) + dist(a_i, f)$$$. The node $$$a_i$$$ is any node from the provided set, for which the number $$$dist(a_i, s) + dist(a_i, f)$$$ is minimal.You can ask no more than $$$14$$$ queries.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"1040"You have an array $$$a$$$ of length $$$n$$$. For every positive integer $$$x$$$ you are going to perform the following operation during the $$$x$$$-th second:  Select some distinct indices $$$i_{1}, i_{2}, \ldots, i_{k}$$$ which are between $$$1$$$ and $$$n$$$ inclusive, and add $$$2^{x-1}$$$ to each corresponding position of $$$a$$$. Formally, $$$a_{i_{j}} := a_{i_{j}} + 2^{x-1}$$$ for $$$j = 1, 2, \ldots, k$$$. Note that you are allowed to not select any indices at all. You have to make $$$a$$$ nondecreasing as fast as possible. Find the smallest number $$$T$$$ such that you can make the array nondecreasing after at most $$$T$$$ seconds.Array $$$a$$$ is nondecreasing if and only if $$$a_{1} \le a_{2} \le \ldots \le a_{n}$$$.You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1041"Vlad and Nastya live in a city consisting of $$$n$$$ houses and $$$n-1$$$ road. From each house, you can get to the other by moving only along the roads. That is, the city is a tree.Vlad lives in a house with index $$$x$$$, and Nastya lives in a house with index $$$y$$$. Vlad decided to visit Nastya. However, he remembered that he had postponed for later $$$k$$$ things that he has to do before coming to Nastya. To do the $$$i$$$-th thing, he needs to come to the $$$a_i$$$-th house, things can be done in any order. In $$$1$$$ minute, he can walk from one house to another if they are connected by a road.Vlad does not really like walking, so he is interested what is the minimum number of minutes he has to spend on the road to do all things and then come to Nastya. Houses $$$a_1, a_2, \dots, a_k$$$ he can visit in any order. He can visit any house multiple times (if he wants).",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"1042"Filled with optimism, Hyunuk will host a conference about how great this new year will be!The conference will have $$$n$$$ lectures. Hyunuk has two candidate venues $$$a$$$ and $$$b$$$. For each of the $$$n$$$ lectures, the speaker specified two time intervals $$$[sa_i, ea_i]$$$ ($$$sa_i \le ea_i$$$) and $$$[sb_i, eb_i]$$$ ($$$sb_i \le eb_i$$$). If the conference is situated in venue $$$a$$$, the lecture will be held from $$$sa_i$$$ to $$$ea_i$$$, and if the conference is situated in venue $$$b$$$, the lecture will be held from $$$sb_i$$$ to $$$eb_i$$$. Hyunuk will choose one of these venues and all lectures will be held at that venue.Two lectures are said to overlap if they share any point in time in common. Formally, a lecture held in interval $$$[x, y]$$$ overlaps with a lecture held in interval $$$[u, v]$$$ if and only if $$$\max(x, u) \le \min(y, v)$$$.We say that a participant can attend a subset $$$s$$$ of the lectures if the lectures in $$$s$$$ do not pairwise overlap (i.e. no two lectures overlap). Note that the possibility of attending may depend on whether Hyunuk selected venue $$$a$$$ or venue $$$b$$$ to hold the conference.A subset of lectures $$$s$$$ is said to be venue-sensitive if, for one of the venues, the participant can attend $$$s$$$, but for the other venue, the participant cannot attend $$$s$$$.A venue-sensitive set is problematic for a participant who is interested in attending the lectures in $$$s$$$ because the participant cannot be sure whether the lecture times will overlap. Hyunuk will be happy if and only if there are no venue-sensitive sets. Determine whether Hyunuk will be happy.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1043"A boy Bob likes to draw. Not long ago he bought a rectangular graph (checked) sheet with n rows and m columns. Bob shaded some of the squares on the sheet. Having seen his masterpiece, he decided to share it with his elder brother, who lives in Flatland. Now Bob has to send his picture by post, but because of the world economic crisis and high oil prices, he wants to send his creation, but to spend as little money as possible. For each sent square of paper (no matter whether it is shaded or not) Bob has to pay 3.14 burles. Please, help Bob cut out of his masterpiece a rectangle of the minimum cost, that will contain all the shaded squares. The rectangle's sides should be parallel to the sheet's sides.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1044"A substring of some string is called the most frequent, if the number of its occurrences is not less than number of occurrences of any other substring.You are given a set of strings. A string (not necessarily from this set) is called good if all elements of the set are the most frequent substrings of this string. Restore the non-empty good string with minimum length. If several such strings exist, restore lexicographically minimum string. If there are no good strings, print ""NO"" (without quotes).A substring of a string is a contiguous subsequence of letters in the string. For example, ""ab"", ""c"", ""abc"" are substrings of string ""abc"", while ""ac"" is not a substring of that string.The number of occurrences of a substring in a string is the number of starting positions in the string where the substring occurs. These occurrences could overlap.String a is lexicographically smaller than string b, if a is a prefix of b, or a has a smaller letter at the first position where a and b differ.","['graphs', 'strings']","[0, 0, 1, 0, 0, 0, 1, 0]"1045"Fox Ciel saw a large field while she was on a bus. The field was a n × m rectangle divided into 1 × 1 cells. Some cells were wasteland, and other each cell contained crop plants: either carrots or kiwis or grapes. After seeing the field carefully, Ciel found that the crop plants of each cell were planted in following procedure:  Assume that the rows are numbered 1 to n from top to bottom and the columns are numbered 1 to m from left to right, and a cell in row i and column j is represented as (i, j).  First, each field is either cultivated or waste. Crop plants will be planted in the cultivated cells in the order of (1, 1) → ... → (1, m) → (2, 1) → ... → (2, m) → ... → (n, 1) → ... → (n, m). Waste cells will be ignored.  Crop plants (either carrots or kiwis or grapes) will be planted in each cell one after another cyclically. Carrots will be planted in the first cell, then kiwis in the second one, grapes in the third one, carrots in the forth one, kiwis in the fifth one, and so on. The following figure will show you the example of this procedure. Here, a white square represents a cultivated cell, and a black square represents a waste cell.  Now she is wondering how to determine the crop plants in some certain cells. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1046"You play a computer game. Your character stands on some level of a multilevel ice cave. In order to move on forward, you need to descend one level lower and the only way to do this is to fall through the ice.The level of the cave where you are is a rectangular square grid of n rows and m columns. Each cell consists either from intact or from cracked ice. From each cell you can move to cells that are side-adjacent with yours (due to some limitations of the game engine you cannot make jumps on the same place, i.e. jump from a cell to itself). If you move to the cell with cracked ice, then your character falls down through it and if you move to the cell with intact ice, then the ice on this cell becomes cracked.Let's number the rows with integers from 1 to n from top to bottom and the columns with integers from 1 to m from left to right. Let's denote a cell on the intersection of the r-th row and the c-th column as (r, c). You are staying in the cell (r1, c1) and this cell is cracked because you've just fallen here from a higher level. You need to fall down through the cell (r2, c2) since the exit to the next level is there. Can you do this?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1047"Berland annual chess tournament is coming!Organizers have gathered 2·n chess players who should be divided into two teams with n people each. The first team is sponsored by BerOil and the second team is sponsored by BerMobile. Obviously, organizers should guarantee the win for the team of BerOil.Thus, organizers should divide all 2·n players into two teams with n people each in such a way that the first team always wins.Every chess player has its rating ri. It is known that chess player with the greater rating always wins the player with the lower rating. If their ratings are equal then any of the players can win.After teams assignment there will come a drawing to form n pairs of opponents: in each pair there is a player from the first team and a player from the second team. Every chess player should be in exactly one pair. Every pair plays once. The drawing is totally random.Is it possible to divide all 2·n players into two teams with n people each so that the player from the first team in every pair wins regardless of the results of the drawing?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1048"You are given an unweighted tree with $$$n$$$ vertices. Recall that a tree is a connected undirected graph without cycles.Your task is to choose three distinct vertices $$$a, b, c$$$ on this tree such that the number of edges which belong to at least one of the simple paths between $$$a$$$ and $$$b$$$, $$$b$$$ and $$$c$$$, or $$$a$$$ and $$$c$$$ is the maximum possible. See the notes section for a better understanding.The simple path is the path that visits each vertex at most once.",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"1049"Medicine faculty of Berland State University has just finished their admission campaign. As usual, about $$$80\%$$$ of applicants are girls and majority of them are going to live in the university dormitory for the next $$$4$$$ (hopefully) years.The dormitory consists of $$$n$$$ rooms and a single mouse! Girls decided to set mouse traps in some rooms to get rid of the horrible monster. Setting a trap in room number $$$i$$$ costs $$$c_i$$$ burles. Rooms are numbered from $$$1$$$ to $$$n$$$.Mouse doesn't sit in place all the time, it constantly runs. If it is in room $$$i$$$ in second $$$t$$$ then it will run to room $$$a_i$$$ in second $$$t + 1$$$ without visiting any other rooms inbetween ($$$i = a_i$$$ means that mouse won't leave room $$$i$$$). It's second $$$0$$$ in the start. If the mouse is in some room with a mouse trap in it, then the mouse get caught into this trap.That would have been so easy if the girls actually knew where the mouse at. Unfortunately, that's not the case, mouse can be in any room from $$$1$$$ to $$$n$$$ at second $$$0$$$.What it the minimal total amount of burles girls can spend to set the traps in order to guarantee that the mouse will eventually be caught no matter the room it started from?",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"1050"Mole is hungry again. He found one ant colony, consisting of n ants, ordered in a row. Each ant i (1 ≤ i ≤ n) has a strength si.In order to make his dinner more interesting, Mole organizes a version of «Hunger Games» for the ants. He chooses two numbers l and r (1 ≤ l ≤ r ≤ n) and each pair of ants with indices between l and r (inclusively) will fight. When two ants i and j fight, ant i gets one battle point only if si divides sj (also, ant j gets one battle point only if sj divides si). After all fights have been finished, Mole makes the ranking. An ant i, with vi battle points obtained, is going to be freed only if vi = r - l, or in other words only if it took a point in every fight it participated. After that, Mole eats the rest of the ants. Note that there can be many ants freed or even none.In order to choose the best sequence, Mole gives you t segments [li, ri] and asks for each of them how many ants is he going to eat if those ants fight.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1051"Sengoku still remembers the mysterious ""colourful meteoroids"" she discovered with Lala-chan when they were little. In particular, one of the nights impressed her deeply, giving her the illusion that all her fancies would be realized.On that night, Sengoku constructed a permutation p1, p2, ..., pn of integers from 1 to n inclusive, with each integer representing a colour, wishing for the colours to see in the coming meteor outburst. Two incredible outbursts then arrived, each with n meteorids, colours of which being integer sequences a1, a2, ..., an and b1, b2, ..., bn respectively. Meteoroids' colours were also between 1 and n inclusive, and the two sequences were not identical, that is, at least one i (1 ≤ i ≤ n) exists, such that ai ≠ bi holds.Well, she almost had it all — each of the sequences a and b matched exactly n - 1 elements in Sengoku's permutation. In other words, there is exactly one i (1 ≤ i ≤ n) such that ai ≠ pi, and exactly one j (1 ≤ j ≤ n) such that bj ≠ pj.For now, Sengoku is able to recover the actual colour sequences a and b through astronomical records, but her wishes have been long forgotten. You are to reconstruct any possible permutation Sengoku could have had on that night.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1052"You've got an array a, consisting of n integers: a1, a2, ..., an. Your task is to find a minimal by inclusion segment [l, r] (1 ≤ l ≤ r ≤ n) such, that among numbers al,  al + 1,  ...,  ar there are exactly k distinct numbers.Segment [l, r] (1 ≤ l ≤ r ≤ n; l, r are integers) of length m = r - l + 1, satisfying the given property, is called minimal by inclusion, if there is no segment [x, y] satisfying the property and less then m in length, such that 1 ≤ l ≤ x ≤ y ≤ r ≤ n. Note that the segment [l, r] doesn't have to be minimal in length among all segments, satisfying the given property.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1053"Thumbelina has had an accident. She has found herself on a little island in the middle of a swamp and wants to get to the shore very much.One can get to the shore only by hills that are situated along a straight line that connects the little island with the shore. Let us assume that the hills are numbered from 1 to n and the number of a hill is equal to the distance in meters between it and the island. The distance between the n-th hill and the shore is also 1 meter.Thumbelina is too small to make such jumps. Fortunately, a family of frogs living in the swamp suggests to help her. Each frog agrees to give Thumbelina a ride but Thumbelina should choose only one frog. Each frog has a certain jump length. If Thumbelina agrees to accept help from a frog whose jump length is d, the frog will jump from the island on the hill d, then — on the hill 2d, then 3d and so on until they get to the shore (i.e. find itself beyond the hill n).However, there is one more problem: mosquitoes also live in the swamp. At the moment they have a siesta, and they are having a nap on some hills. If the frog jumps on a hill with a mosquito the frog will smash it. The frogs Thumbelina has met are pacifists, so they will find the death of each mosquito very much sad. Help Thumbelina choose a frog that will bring her to the shore and smash as small number of mosquitoes as possible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1054"Martha — as a professional problemsetter — proposed a problem for a world-class contest. This is the problem statement:Tomorrow is Nadia's birthday, and Bardia (her brother) is assigned to make the balloons ready!There are n balloons (initially empty) that are tied to a straight line on certain positions x1, x2, ..., xn. Bardia inflates the balloons from left to right. As a result, i-th balloon gets bigger and bigger until its radius reaches the pressure endurance pi or it touches another previously-inflated balloon.  While Bardia was busy with the balloons, he wondered ""What will be the sum of radius of balloons after all of the balloons are inflated?"". Being a nerdy type of guy, he is now thinking about the problem instead of preparing his sister's birthday. Calculate the answer to Bardia's problem so that Nadia's birthday won't be balloon-less.Artha — Martha's student — claimed his solution got accepted. Martha (being his teacher for a long time!) knew he couldn't have solved the problem for real and thus thinks there is something wrong with the testcases. Artha isn't anyhow logical, which means there is no way for Martha to explain the wrong point in his algorithm. So, the only way is to find a testcase to prove him wrong!Artha's pseudo-code is shown below:  You should output a small testcase for the problem such that Artha's algorithm is incorrect. The algorithm's output is considered correct if it differs from the correct value by no more than 1.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1055"Blake is a CEO of a large company called ""Blake Technologies"". He loves his company very much and he thinks that his company should be the best. That is why every candidate needs to pass through the interview that consists of the following problem.We define function f(x, l, r) as a bitwise OR of integers xl, xl + 1, ..., xr, where xi is the i-th element of the array x. You are given two arrays a and b of length n. You need to determine the maximum value of sum f(a, l, r) + f(b, l, r) among all possible 1 ≤ l ≤ r ≤ n.  ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1056"  This is an interactive problem.We picked an array of whole numbers $$$a_1, a_2, \ldots, a_n$$$ ($$$0 \le a_i \le 10^9$$$) and concealed exactly one zero in it! Your goal is to find the location of this zero, that is, to find $$$i$$$ such that $$$a_i = 0$$$.You are allowed to make several queries to guess the answer. For each query, you can think up three distinct indices $$$i, j, k$$$, and we will tell you the value of $$$\max(a_i, a_j, a_k) - \min(a_i, a_j, a_k)$$$. In other words, we will tell you the difference between the maximum and the minimum number among $$$a_i$$$, $$$a_j$$$ and $$$a_k$$$.You are allowed to make no more than $$$2 \cdot n - 2$$$ queries, and after that you have two tries to guess where the zero is. That is, you have to tell us two numbers $$$i$$$ and $$$j$$$ and you win if $$$a_i = 0$$$ or $$$a_j = 0$$$.Can you guess where we hid the zero?Note that the array in each test case is fixed beforehand and will not change during the game. In other words, the interactor is not adaptive.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1057" Denis, after buying flowers and sweets (you will learn about this story in the next task), went to a date with Nastya to ask her to become a couple. Now, they are sitting in the cafe and finally... Denis asks her to be together, but ... Nastya doesn't give any answer. The poor boy was very upset because of that. He was so sad that he punched some kind of scoreboard with numbers. The numbers are displayed in the same way as on an electronic clock: each digit position consists of $$$7$$$ segments, which can be turned on or off to display different numbers. The picture shows how all $$$10$$$ decimal digits are displayed:   After the punch, some segments stopped working, that is, some segments might stop glowing if they glowed earlier. But Denis remembered how many sticks were glowing and how many are glowing now. Denis broke exactly $$$k$$$ segments and he knows which sticks are working now. Denis came up with the question: what is the maximum possible number that can appear on the board if you turn on exactly $$$k$$$ sticks (which are off now)? It is allowed that the number includes leading zeros.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1058"You are given an undirected tree of $$$n$$$ vertices. Some vertices are colored blue, some are colored red and some are uncolored. It is guaranteed that the tree contains at least one red vertex and at least one blue vertex.You choose an edge and remove it from the tree. Tree falls apart into two connected components. Let's call an edge nice if neither of the resulting components contain vertices of both red and blue colors.How many nice edges are there in the given tree?",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"1059"In a small restaurant there are a tables for one person and b tables for two persons. It it known that n groups of people come today, each consisting of one or two people. If a group consist of one person, it is seated at a vacant one-seater table. If there are none of them, it is seated at a vacant two-seater table. If there are none of them, it is seated at a two-seater table occupied by single person. If there are still none of them, the restaurant denies service to this group.If a group consist of two people, it is seated at a vacant two-seater table. If there are none of them, the restaurant denies service to this group.You are given a chronological order of groups coming. You are to determine the total number of people the restaurant denies service to.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1060"Nastia has received an array of $$$n$$$ positive integers as a gift.She calls such an array $$$a$$$ good that for all $$$i$$$ ($$$2 \le i \le n$$$) takes place $$$gcd(a_{i - 1}, a_{i}) = 1$$$, where $$$gcd(u, v)$$$ denotes the greatest common divisor (GCD) of integers $$$u$$$ and $$$v$$$.You can perform the operation: select two different indices $$$i, j$$$ ($$$1 \le i, j \le n$$$, $$$i \neq j$$$) and two integers $$$x, y$$$ ($$$1 \le x, y \le 2 \cdot 10^9$$$) so that $$$\min{(a_i, a_j)} = \min{(x, y)}$$$. Then change $$$a_i$$$ to $$$x$$$ and $$$a_j$$$ to $$$y$$$.The girl asks you to make the array good using at most $$$n$$$ operations.It can be proven that this is always possible.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1061"During the archaeological research in the Middle East you found the traces of three ancient religions: First religion, Second religion and Third religion. You compiled the information on the evolution of each of these beliefs, and you now wonder if the followers of each religion could coexist in peace.The Word of Universe is a long word containing the lowercase English characters only. At each moment of time, each of the religion beliefs could be described by a word consisting of lowercase English characters.The three religions can coexist in peace if their descriptions form disjoint subsequences of the Word of Universe. More formally, one can paint some of the characters of the Word of Universe in three colors: $$$1$$$, $$$2$$$, $$$3$$$, so that each character is painted in at most one color, and the description of the $$$i$$$-th religion can be constructed from the Word of Universe by removing all characters that aren't painted in color $$$i$$$.The religions however evolve. In the beginning, each religion description is empty. Every once in a while, either a character is appended to the end of the description of a single religion, or the last character is dropped from the description. After each change, determine if the religions could coexist in peace.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1062"Nastya baked $$$m$$$ pancakes and spread them on $$$n$$$ dishes. The dishes are in a row and numbered from left to right. She put $$$a_i$$$ pancakes on the dish with the index $$$i$$$.Seeing the dishes, Vlad decided to bring order to the stacks and move some pancakes. In one move, he can shift one pancake from any dish to the closest one, that is, select the dish $$$i$$$ ($$$a_i > 0$$$) and do one of the following: if $$$i > 1$$$, put the pancake on a dish with the previous index, after this move $$$a_i = a_i - 1$$$ and $$$a_{i - 1} = a_{i - 1} + 1$$$; if $$$i < n$$$, put the pancake on a dish with the following index, after this move $$$a_i = a_i - 1$$$ and $$$a_{i + 1} = a_{i + 1} + 1$$$.Vlad wants to make the array $$$a$$$non-increasing, after moving as few pancakes as possible. Help him find the minimum number of moves needed for this.The array $$$a=[a_1, a_2,\dots,a_n]$$$ is called non-increasing if $$$a_i \ge a_{i+1}$$$ for all $$$i$$$ from $$$1$$$ to $$$n-1$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1063"It's been almost a week since Polycarp couldn't get rid of insomnia. And as you may already know, one week in Berland lasts k days!When Polycarp went to a doctor with his problem, the doctor asked him about his sleeping schedule (more specifically, the average amount of hours of sleep per week). Luckily, Polycarp kept records of sleep times for the last n days. So now he has a sequence a1, a2, ..., an, where ai is the sleep time on the i-th day.The number of records is so large that Polycarp is unable to calculate the average value by himself. Thus he is asking you to help him with the calculations. To get the average Polycarp is going to consider k consecutive days as a week. So there will be n - k + 1 weeks to take into consideration. For example, if k = 2, n = 3 and a = [3, 4, 7], then the result is .You should write a program which will calculate average sleep times of Polycarp over all weeks.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1064"Let $$$\mathsf{AND}$$$ denote the bitwise AND operation, and $$$\mathsf{OR}$$$ denote the bitwise OR operation.You are given an array $$$a$$$ of length $$$n$$$ and a non-negative integer $$$k$$$. You can perform at most $$$k$$$ operations on the array of the following type:  Select an index $$$i$$$ ($$$1 \leq i \leq n$$$) and replace $$$a_i$$$ with $$$a_i$$$ $$$\mathsf{OR}$$$ $$$2^j$$$ where $$$j$$$ is any integer between $$$0$$$ and $$$30$$$ inclusive. In other words, in an operation you can choose an index $$$i$$$ ($$$1 \leq i \leq n$$$) and set the $$$j$$$-th bit of $$$a_i$$$ to $$$1$$$ ($$$0 \leq j \leq 30$$$). Output the maximum possible value of $$$a_1$$$ $$$\mathsf{AND}$$$ $$$a_2$$$ $$$\mathsf{AND}$$$ $$$\dots$$$ $$$\mathsf{AND}$$$ $$$a_n$$$ after performing at most $$$k$$$ operations. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1065"You are given a string $$$s$$$ of length $$$n$$$ consisting only of lowercase Latin letters.A substring of a string is a contiguous subsequence of that string. So, string ""forces"" is substring of string ""codeforces"", but string ""coder"" is not.Your task is to calculate the number of ways to remove exactly one substring from this string in such a way that all remaining characters are equal (the number of distinct characters either zero or one).It is guaranteed that there is at least two different characters in $$$s$$$.Note that you can remove the whole string and it is correct. Also note that you should remove at least one character.Since the answer can be rather large (not very large though) print it modulo $$$998244353$$$.If you are Python programmer, consider using PyPy instead of Python when you submit your code.","['math', 'strings']","[0, 0, 0, 1, 0, 0, 1, 0]"1066"An African crossword is a rectangular table n × m in size. Each cell of the table contains exactly one letter. This table (it is also referred to as grid) contains some encrypted word that needs to be decoded.To solve the crossword you should cross out all repeated letters in rows and columns. In other words, a letter should only be crossed out if and only if the corresponding column or row contains at least one more letter that is exactly the same. Besides, all such letters are crossed out simultaneously.When all repeated letters have been crossed out, we should write the remaining letters in a string. The letters that occupy a higher position follow before the letters that occupy a lower position. If the letters are located in one row, then the letter to the left goes first. The resulting word is the answer to the problem.You are suggested to solve an African crossword and print the word encrypted there.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1067"Codefortia is a small island country located somewhere in the West Pacific. It consists of $$$n$$$ settlements connected by $$$m$$$ bidirectional gravel roads. Curiously enough, the beliefs of the inhabitants require the time needed to pass each road to be equal either to $$$a$$$ or $$$b$$$ seconds. It's guaranteed that one can go between any pair of settlements by following a sequence of roads.Codefortia was recently struck by the financial crisis. Therefore, the king decided to abandon some of the roads so that:  it will be possible to travel between each pair of cities using the remaining roads only,  the sum of times required to pass each remaining road will be minimum possible (in other words, remaining roads must form minimum spanning tree, using the time to pass the road as its weight),  among all the plans minimizing the sum of times above, the time required to travel between the king's residence (in settlement $$$1$$$) and the parliament house (in settlement $$$p$$$) using the remaining roads only will be minimum possible. The king, however, forgot where the parliament house was. For each settlement $$$p = 1, 2, \dots, n$$$, can you tell what is the minimum time required to travel between the king's residence and the parliament house (located in settlement $$$p$$$) after some roads are abandoned?",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"1068"There will be a launch of a new, powerful and unusual collider very soon, which located along a straight line. n particles will be launched inside it. All of them are located in a straight line and there can not be two or more particles located in the same point. The coordinates of the particles coincide with the distance in meters from the center of the collider, xi is the coordinate of the i-th particle and its position in the collider at the same time. All coordinates of particle positions are even integers.You know the direction of each particle movement — it will move to the right or to the left after the collider's launch start. All particles begin to move simultaneously at the time of the collider's launch start. Each particle will move straight to the left or straight to the right with the constant speed of 1 meter per microsecond. The collider is big enough so particles can not leave it in the foreseeable time.Write the program which finds the moment of the first collision of any two particles of the collider. In other words, find the number of microseconds before the first moment when any two particles are at the same point.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1069"Please notice the unusual memory limit of this problem.Orac likes games. Recently he came up with the new game, ""Game of Life"".You should play this game on a black and white grid with $$$n$$$ rows and $$$m$$$ columns. Each cell is either black or white.For each iteration of the game (the initial iteration is $$$0$$$), the color of each cell will change under the following rules: If there are no adjacent cells with the same color as this cell on the current iteration, the color of it on the next iteration will be the same. Otherwise, the color of the cell on the next iteration will be different.Two cells are adjacent if they have a mutual edge.Now Orac has set an initial situation, and he wants to know for the cell $$$(i,j)$$$ (in $$$i$$$-th row and $$$j$$$-th column), what will be its color at the iteration $$$p$$$. He may ask you these questions several times. ",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"1070"Chubby Yang is studying linear equations right now. He came up with a nice problem. In the problem you are given an n × n matrix W, consisting of integers, and you should find two n × n matrices A and B, all the following conditions must hold:   Aij = Aji, for all i, j (1 ≤ i, j ≤ n);  Bij =  - Bji, for all i, j (1 ≤ i, j ≤ n);  Wij = Aij + Bij, for all i, j (1 ≤ i, j ≤ n). Can you solve the problem?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1071"n soldiers stand in a circle. For each soldier his height ai is known. A reconnaissance unit can be made of such two neighbouring soldiers, whose heights difference is minimal, i.e. |ai - aj| is minimal. So each of them will be less noticeable with the other. Output any pair of soldiers that can form a reconnaissance unit.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1072"There are n employees working in company ""X"" (let's number them from 1 to n for convenience). Initially the employees didn't have any relationships among each other. On each of m next days one of the following events took place:  either employee y became the boss of employee x (at that, employee x didn't have a boss before);  or employee x gets a packet of documents and signs them; then he gives the packet to his boss. The boss signs the documents and gives them to his boss and so on (the last person to sign the documents sends them to the archive);  or comes a request of type ""determine whether employee x signs certain documents"". Your task is to write a program that will, given the events, answer the queries of the described type. At that, it is guaranteed that throughout the whole working time the company didn't have cyclic dependencies.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"1073"PizzaForces is Petya's favorite pizzeria. PizzaForces makes and sells pizzas of three sizes: small pizzas consist of $$$6$$$ slices, medium ones consist of $$$8$$$ slices, and large pizzas consist of $$$10$$$ slices each. Baking them takes $$$15$$$, $$$20$$$ and $$$25$$$ minutes, respectively.Petya's birthday is today, and $$$n$$$ of his friends will come, so he decided to make an order from his favorite pizzeria. Petya wants to order so much pizza that each of his friends gets at least one slice of pizza. The cooking time of the order is the total baking time of all the pizzas in the order.Your task is to determine the minimum number of minutes that is needed to make pizzas containing at least $$$n$$$ slices in total. For example:   if $$$12$$$ friends come to Petya's birthday, he has to order pizzas containing at least $$$12$$$ slices in total. He can order two small pizzas, containing exactly $$$12$$$ slices, and the time to bake them is $$$30$$$ minutes;  if $$$15$$$ friends come to Petya's birthday, he has to order pizzas containing at least $$$15$$$ slices in total. He can order a small pizza and a large pizza, containing $$$16$$$ slices, and the time to bake them is $$$40$$$ minutes;  if $$$300$$$ friends come to Petya's birthday, he has to order pizzas containing at least $$$300$$$ slices in total. He can order $$$15$$$ small pizzas, $$$10$$$ medium pizzas and $$$13$$$ large pizzas, in total they contain $$$15 \cdot 6 + 10 \cdot 8 + 13 \cdot 10 = 300$$$ slices, and the total time to bake them is $$$15 \cdot 15 + 10 \cdot 20 + 13 \cdot 25 = 750$$$ minutes;  if only one friend comes to Petya's birthday, he can order a small pizza, and the time to bake it is $$$15$$$ minutes. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1074"Define the score of some binary string $$$T$$$ as the absolute difference between the number of zeroes and ones in it. (for example, $$$T=$$$ 010001 contains $$$4$$$ zeroes and $$$2$$$ ones, so the score of $$$T$$$ is $$$|4-2| = 2$$$).Define the creepiness of some binary string $$$S$$$ as the maximum score among all of its prefixes (for example, the creepiness of $$$S=$$$ 01001 is equal to $$$2$$$ because the score of the prefix $$$S[1 \ldots 4]$$$ is $$$2$$$ and the rest of the prefixes have a score of $$$2$$$ or less).Given two integers $$$a$$$ and $$$b$$$, construct a binary string consisting of $$$a$$$ zeroes and $$$b$$$ ones with the minimum possible creepiness.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1075"Inna is a great piano player and Dima is a modest guitar player. Dima has recently written a song and they want to play it together. Of course, Sereja wants to listen to the song very much. A song is a sequence of notes. Dima and Inna want to play each note at the same time. At that, they can play the i-th note at volume v (1 ≤ v ≤ ai; v is an integer) both on the piano and the guitar. They should retain harmony, so the total volume with which the i-th note was played on the guitar and the piano must equal bi. If Dima and Inna cannot play a note by the described rules, they skip it and Sereja's joy drops by 1. But if Inna and Dima play the i-th note at volumes xi and yi (xi + yi = bi) correspondingly, Sereja's joy rises by xi·yi. Sereja has just returned home from the university and his current joy is 0. Help Dima and Inna play the song so as to maximize Sereja's total joy after listening to the whole song!",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1076"You have $$$n$$$ barrels lined up in a row, numbered from left to right from one. Initially, the $$$i$$$-th barrel contains $$$a_i$$$ liters of water.You can pour water from one barrel to another. In one act of pouring, you can choose two different barrels $$$x$$$ and $$$y$$$ (the $$$x$$$-th barrel shouldn't be empty) and pour any possible amount of water from barrel $$$x$$$ to barrel $$$y$$$ (possibly, all water). You may assume that barrels have infinite capacity, so you can pour any amount of water in each of them. Calculate the maximum possible difference between the maximum and the minimum amount of water in the barrels, if you can pour water at most $$$k$$$ times.Some examples:   if you have four barrels, each containing $$$5$$$ liters of water, and $$$k = 1$$$, you may pour $$$5$$$ liters from the second barrel into the fourth, so the amounts of water in the barrels are $$$[5, 0, 5, 10]$$$, and the difference between the maximum and the minimum is $$$10$$$;  if all barrels are empty, you can't make any operation, so the difference between the maximum and the minimum amount is still $$$0$$$. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1077"You are given two integers $$$l$$$ and $$$r$$$, $$$l\le r$$$. Find the largest possible value of $$$a \bmod b$$$ over all pairs $$$(a, b)$$$ of integers for which $$$r\ge a \ge b \ge l$$$.As a reminder, $$$a \bmod b$$$ is a remainder we get when dividing $$$a$$$ by $$$b$$$. For example, $$$26 \bmod 8 = 2$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1078"After Misha's birthday he had many large numbers left, scattered across the room. Now it's time to clean up and Misha needs to put them in a basket. He ordered this task to his pet robot that agreed to complete the task at certain conditions. Before the robot puts a number x to the basket, Misha should answer the question: is it possible to choose one or multiple numbers that already are in the basket, such that their XOR sum equals x? If the answer is positive, you also need to give the indexes of these numbers. If there are multiple options of choosing numbers, you are allowed to choose any correct option. After Misha's answer the robot puts the number to the basket.Initially the basket is empty. Each integer you put in the basket takes some number. The first integer you put into the basket take number 0, the second integer takes number 1 and so on.Misha needs to clean up the place as soon as possible but unfortunately, he isn't that good at mathematics. He asks you to help him.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1079"Igor is a post-graduate student of chemistry faculty in Berland State University (BerSU). He needs to conduct a complicated experiment to write his thesis, but laboratory of BerSU doesn't contain all the materials required for this experiment.Fortunately, chemical laws allow material transformations (yes, chemistry in Berland differs from ours). But the rules of transformation are a bit strange.Berland chemists are aware of n materials, numbered in the order they were discovered. Each material can be transformed into some other material (or vice versa). Formally, for each i (2 ≤ i ≤ n) there exist two numbers xi and ki that denote a possible transformation: ki kilograms of material xi can be transformed into 1 kilogram of material i, and 1 kilogram of material i can be transformed into 1 kilogram of material xi. Chemical processing equipment in BerSU allows only such transformation that the amount of resulting material is always an integer number of kilograms.For each i (1 ≤ i ≤ n) Igor knows that the experiment requires ai kilograms of material i, and the laboratory contains bi kilograms of this material. Is it possible to conduct an experiment after transforming some materials (or none)?",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"1080"You are given an integer $$$n$$$.You should find a list of pairs $$$(x_1, y_1)$$$, $$$(x_2, y_2)$$$, ..., $$$(x_q, y_q)$$$ ($$$1 \leq x_i, y_i \leq n$$$) satisfying the following condition.Let's consider some function $$$f: \mathbb{N} \times \mathbb{N} \to \mathbb{N}$$$ (we define $$$\mathbb{N}$$$ as the set of positive integers). In other words, $$$f$$$ is a function that returns a positive integer for a pair of positive integers.Let's make an array $$$a_1, a_2, \ldots, a_n$$$, where $$$a_i = i$$$ initially.You will perform $$$q$$$ operations, in $$$i$$$-th of them you will:   assign $$$t = f(a_{x_i}, a_{y_i})$$$ ($$$t$$$ is a temporary variable, it is used only for the next two assignments);  assign $$$a_{x_i} = t$$$;  assign $$$a_{y_i} = t$$$. In other words, you need to simultaneously change $$$a_{x_i}$$$ and $$$a_{y_i}$$$ to $$$f(a_{x_i}, a_{y_i})$$$. Note that during this process $$$f(p, q)$$$ is always the same for a fixed pair of $$$p$$$ and $$$q$$$.In the end, there should be at most two different numbers in the array $$$a$$$.It should be true for any function $$$f$$$.Find any possible list of pairs. The number of pairs should not exceed $$$5 \cdot 10^5$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1081"Alice guesses the strings that Bob made for her.At first, Bob came up with the secret string $$$a$$$ consisting of lowercase English letters. The string $$$a$$$ has a length of $$$2$$$ or more characters. Then, from string $$$a$$$ he builds a new string $$$b$$$ and offers Alice the string $$$b$$$ so that she can guess the string $$$a$$$.Bob builds $$$b$$$ from $$$a$$$ as follows: he writes all the substrings of length $$$2$$$ of the string $$$a$$$ in the order from left to right, and then joins them in the same order into the string $$$b$$$.For example, if Bob came up with the string $$$a$$$=""abac"", then all the substrings of length $$$2$$$ of the string $$$a$$$ are: ""ab"", ""ba"", ""ac"". Therefore, the string $$$b$$$=""abbaac"".You are given the string $$$b$$$. Help Alice to guess the string $$$a$$$ that Bob came up with. It is guaranteed that $$$b$$$ was built according to the algorithm given above. It can be proved that the answer to the problem is unique.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1082"You are given a set of points $$$x_1$$$, $$$x_2$$$, ..., $$$x_n$$$ on the number line.Two points $$$i$$$ and $$$j$$$ can be matched with each other if the following conditions hold:  neither $$$i$$$ nor $$$j$$$ is matched with any other point;  $$$|x_i - x_j| \ge z$$$. What is the maximum number of pairs of points you can match with each other?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1083"You are given a permutation $$$a_1,a_2,\ldots,a_n$$$ of integers from $$$0$$$ to $$$n - 1$$$. Your task is to find how many permutations $$$b_1,b_2,\ldots,b_n$$$ are similar to permutation $$$a$$$. Two permutations $$$a$$$ and $$$b$$$ of size $$$n$$$ are considered similar if for all intervals $$$[l,r]$$$ ($$$1 \le l \le r \le n$$$), the following condition is satisfied: $$$$$$\operatorname{MEX}([a_l,a_{l+1},\ldots,a_r])=\operatorname{MEX}([b_l,b_{l+1},\ldots,b_r]),$$$$$$ where the $$$\operatorname{MEX}$$$ of a collection of integers $$$c_1,c_2,\ldots,c_k$$$ is defined as the smallest non-negative integer $$$x$$$ which does not occur in collection $$$c$$$. For example, $$$\operatorname{MEX}([1,2,3,4,5])=0$$$, and $$$\operatorname{MEX}([0,1,2,4,5])=3$$$.Since the total number of such permutations can be very large, you will have to print its remainder modulo $$$10^9+7$$$.In this problem, a permutation of size $$$n$$$ is an array consisting of $$$n$$$ distinct integers from $$$0$$$ to $$$n-1$$$ in arbitrary order. For example, $$$[1,0,2,4,3]$$$ is a permutation, while $$$[0,1,1]$$$ is not, since $$$1$$$ appears twice in the array. $$$[0,1,3]$$$ is also not a permutation, since $$$n=3$$$ and there is a $$$3$$$ in the array.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1084"In Berland a bus travels along the main street of the capital. The street begins from the main square and looks like a very long segment. There are n bus stops located along the street, the i-th of them is located at the distance ai from the central square, all distances are distinct, the stops are numbered in the order of increasing distance from the square, that is, ai < ai + 1 for all i from 1 to n - 1. The bus starts its journey from the first stop, it passes stops 2, 3 and so on. It reaches the stop number n, turns around and goes in the opposite direction to stop 1, passing all the intermediate stops in the reverse order. After that, it again starts to move towards stop n. During the day, the bus runs non-stop on this route.The bus is equipped with the Berland local positioning system. When the bus passes a stop, the system notes down its number.One of the key features of the system is that it can respond to the queries about the distance covered by the bus for the parts of its path between some pair of stops. A special module of the system takes the input with the information about a set of stops on a segment of the path, a stop number occurs in the set as many times as the bus drove past it. This module returns the length of the traveled segment of the path (or -1 if it is impossible to determine the length uniquely). The operation of the module is complicated by the fact that stop numbers occur in the request not in the order they were visited but in the non-decreasing order.For example, if the number of stops is 6, and the part of the bus path starts at the bus stop number 5, ends at the stop number 3 and passes the stops as follows: , then the request about this segment of the path will have form: 3, 4, 5, 5, 6. If the bus on the segment of the path from stop 5 to stop 3 has time to drive past the 1-th stop (i.e., if we consider a segment that ends with the second visit to stop 3 on the way from 5), then the request will have form: 1, 2, 2, 3, 3, 4, 5, 5, 6.You will have to repeat the Berland programmers achievement and implement this function.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1085"Well, here is another math class task. In mathematics, GCD is the greatest common divisor, and it's an easy task to calculate the GCD between two positive integers.A common divisor for two positive numbers is a number which both numbers are divisible by.But your teacher wants to give you a harder task, in this task you have to find the greatest common divisor d between two integers a and b that is in a given range from low to high (inclusive), i.e. low ≤ d ≤ high. It is possible that there is no common divisor in the given range.You will be given the two integers a and b, then n queries. Each query is a range from low to high and you have to answer each query.",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"1086"Kuzya started going to school. He was given math homework in which he was given an array $$$a$$$ of length $$$n$$$ and an array of symbols $$$b$$$ of length $$$n$$$, consisting of symbols '*' and '/'.Let's denote a path of calculations for a segment $$$[l; r]$$$ ($$$1 \le l \le r \le n$$$) in the following way:   Let $$$x=1$$$ initially. For every $$$i$$$ from $$$l$$$ to $$$r$$$ we will consequently do the following: if $$$b_i=$$$ '*', $$$x=x*a_i$$$, and if $$$b_i=$$$ '/', then $$$x=\frac{x}{a_i}$$$. Let's call a path of calculations for the segment $$$[l; r]$$$ a list of all $$$x$$$ that we got during the calculations (the number of them is exactly $$$r - l + 1$$$). For example, let $$$a=[7,$$$ $$$12,$$$ $$$3,$$$ $$$5,$$$ $$$4,$$$ $$$10,$$$ $$$9]$$$, $$$b=[/,$$$ $$$*,$$$ $$$/,$$$ $$$/,$$$ $$$/,$$$ $$$*,$$$ $$$*]$$$, $$$l=2$$$, $$$r=6$$$, then the path of calculations for that segment is $$$[12,$$$ $$$4,$$$ $$$0.8,$$$ $$$0.2,$$$ $$$2]$$$.Let's call a segment $$$[l;r]$$$ simple if the path of calculations for it contains only integer numbers. Kuzya needs to find the number of simple segments $$$[l;r]$$$ ($$$1 \le l \le r \le n$$$). Since he obviously has no time and no interest to do the calculations for each option, he asked you to write a program to get to find that number!",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"1087"You are given an array consisting of $$$n$$$ integers $$$a_1, a_2, \dots, a_n$$$, and a positive integer $$$m$$$. It is guaranteed that $$$m$$$ is a divisor of $$$n$$$.In a single move, you can choose any position $$$i$$$ between $$$1$$$ and $$$n$$$ and increase $$$a_i$$$ by $$$1$$$.Let's calculate $$$c_r$$$ ($$$0 \le r \le m-1)$$$ — the number of elements having remainder $$$r$$$ when divided by $$$m$$$. In other words, for each remainder, let's find the number of corresponding elements in $$$a$$$ with that remainder.Your task is to change the array in such a way that $$$c_0 = c_1 = \dots = c_{m-1} = \frac{n}{m}$$$.Find the minimum number of moves to satisfy the above requirement.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1088"Many years ago Berland was a small country where only $$$n$$$ people lived. Each person had some savings: the $$$i$$$-th one had $$$a_i$$$ burles.The government considered a person as wealthy if he had at least $$$x$$$ burles. To increase the number of wealthy people Berland decided to carry out several reforms. Each reform looked like that:   the government chooses some subset of people (maybe all of them);  the government takes all savings from the chosen people and redistributes the savings among the chosen people equally. For example, consider the savings as list $$$[5, 1, 2, 1]$$$: if the government chose the $$$1$$$-st and the $$$3$$$-rd persons then it, at first, will take all $$$5 + 2 = 7$$$ burles and after that will return $$$3.5$$$ burles to the chosen people. As a result, the savings will become $$$[3.5, 1, 3.5, 1]$$$.A lot of data was lost from that time, so we don't know how many reforms were implemented and to whom. All we can do is ask you to calculate the maximum possible number of wealthy people after several (maybe zero) reforms.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1089"The Berland language consists of words having exactly two letters. Moreover, the first letter of a word is different from the second letter. Any combination of two different Berland letters (which, by the way, are the same as the lowercase letters of Latin alphabet) is a correct word in Berland language.The Berland dictionary contains all words of this language. The words are listed in a way they are usually ordered in dictionaries. Formally, word $$$a$$$ comes earlier than word $$$b$$$ in the dictionary if one of the following conditions hold:  the first letter of $$$a$$$ is less than the first letter of $$$b$$$;  the first letters of $$$a$$$ and $$$b$$$ are the same, and the second letter of $$$a$$$ is less than the second letter of $$$b$$$. So, the dictionary looks like that:  Word $$$1$$$: ab  Word $$$2$$$: ac  ...  Word $$$25$$$: az  Word $$$26$$$: ba  Word $$$27$$$: bc  ...  Word $$$649$$$: zx  Word $$$650$$$: zy You are given a word $$$s$$$ from the Berland language. Your task is to find its index in the dictionary.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1090"Boboniu likes playing chess with his employees. As we know, no employee can beat the boss in the chess game, so Boboniu has never lost in any round.You are a new applicant for his company. Boboniu will test you with the following chess question:Consider a $$$n\times m$$$ grid (rows are numbered from $$$1$$$ to $$$n$$$, and columns are numbered from $$$1$$$ to $$$m$$$). You have a chess piece, and it stands at some cell $$$(S_x,S_y)$$$ which is not on the border (i.e. $$$2 \le S_x \le n-1$$$ and $$$2 \le S_y \le m-1$$$).From the cell $$$(x,y)$$$, you can move your chess piece to $$$(x,y')$$$ ($$$1\le y'\le m, y' \neq y$$$) or $$$(x',y)$$$ ($$$1\le x'\le n, x'\neq x$$$). In other words, the chess piece moves as a rook. From the cell, you can move to any cell on the same row or column.Your goal is to visit each cell exactly once. Can you find a solution?Note that cells on the path between two adjacent cells in your route are not counted as visited, and it is not required to return to the starting point.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1091"Amugae has a hotel consisting of $$$10$$$ rooms. The rooms are numbered from $$$0$$$ to $$$9$$$ from left to right.The hotel has two entrances — one from the left end, and another from the right end. When a customer arrives to the hotel through the left entrance, they are assigned to an empty room closest to the left entrance. Similarly, when a customer arrives at the hotel through the right entrance, they are assigned to an empty room closest to the right entrance.One day, Amugae lost the room assignment list. Thankfully Amugae's memory is perfect, and he remembers all of the customers: when a customer arrived, from which entrance, and when they left the hotel. Initially the hotel was empty. Write a program that recovers the room assignment list from Amugae's memory.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1092"Roger is a robot. He has an arm that is a series of n segments connected to each other. The endpoints of the i-th segment are initially located at points (i - 1, 0) and (i, 0). The endpoint at (i - 1, 0) is colored red and the endpoint at (i, 0) is colored blue for all segments. Thus, the blue endpoint of the i-th segment is touching the red endpoint of the (i + 1)-th segment for all valid i.Roger can move his arm in two different ways:   He can choose some segment and some value. This is denoted as choosing the segment number i and picking some positive l. This change happens as follows: the red endpoint of segment number i and segments from 1 to i - 1 are all fixed in place. Imagine a ray from the red endpoint to the blue endpoint. The blue endpoint and segments i + 1 through n are translated l units in the direction of this ray.   In this picture, the red point labeled A and segments before A stay in place, while the blue point labeled B and segments after B gets translated. He can choose a segment and rotate it. This is denoted as choosing the segment number i, and an angle a. The red endpoint of the i-th segment will stay fixed in place. The blue endpoint of that segment and segments i + 1 to n will rotate clockwise by an angle of a degrees around the red endpoint.   In this picture, the red point labeled A and segments before A stay in place, while the blue point labeled B and segments after B get rotated around point A. Roger will move his arm m times. These transformations are a bit complicated, and Roger easily loses track of where the blue endpoint of the last segment is. Help him compute the coordinates of the blue endpoint of the last segment after applying each operation. Note that these operations are cumulative, and Roger's arm may intersect itself arbitrarily during the moves.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"1093"Polycarp is sad — New Year is coming in few days but there is still no snow in his city. To bring himself New Year mood, he decided to decorate his house with some garlands.The local store introduced a new service this year, called ""Build your own garland"". So you can buy some red, green and blue lamps, provide them and the store workers will solder a single garland of them. The resulting garland will have all the lamps you provided put in a line. Moreover, no pair of lamps of the same color will be adjacent to each other in this garland!For example, if you provide $$$3$$$ red, $$$3$$$ green and $$$3$$$ blue lamps, the resulting garland can look like this: ""RGBRBGBGR"" (""RGB"" being the red, green and blue color, respectively). Note that it's ok to have lamps of the same color on the ends of the garland.However, if you provide, say, $$$1$$$ red, $$$10$$$ green and $$$2$$$ blue lamps then the store workers won't be able to build any garland of them. Any garland consisting of these lamps will have at least one pair of lamps of the same color adjacent to each other. Note that the store workers should use all the lamps you provided.So Polycarp has bought some sets of lamps and now he wants to know if the store workers can build a garland from each of them.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1094"Given a set of integers (it can contain equal elements).You have to split it into two subsets $$$A$$$ and $$$B$$$ (both of them can contain equal elements or be empty). You have to maximize the value of $$$mex(A)+mex(B)$$$.Here $$$mex$$$ of a set denotes the smallest non-negative integer that doesn't exist in the set. For example:   $$$mex(\{1,4,0,2,2,1\})=3$$$  $$$mex(\{3,3,2,1,3,0,0\})=4$$$  $$$mex(\varnothing)=0$$$ ($$$mex$$$ for empty set) The set is splitted into two subsets $$$A$$$ and $$$B$$$ if for any integer number $$$x$$$ the number of occurrences of $$$x$$$ into this set is equal to the sum of the number of occurrences of $$$x$$$ into $$$A$$$ and the number of occurrences of $$$x$$$ into $$$B$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1095"Polycarp got an array of integers $$$a[1 \dots n]$$$ as a gift. Now he wants to perform a certain number of operations (possibly zero) so that all elements of the array become the same (that is, to become $$$a_1=a_2=\dots=a_n$$$). In one operation, he can take some indices in the array and increase the elements of the array at those indices by $$$1$$$.For example, let $$$a=[4,2,1,6,2]$$$. He can perform the following operation: select indices 1, 2, and 4 and increase elements of the array in those indices by $$$1$$$. As a result, in one operation, he can get a new state of the array $$$a=[5,3,1,7,2]$$$.What is the minimum number of operations it can take so that all elements of the array become equal to each other (that is, to become $$$a_1=a_2=\dots=a_n$$$)?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1096"There are $$$n$$$ rectangles in a row. You can either turn each rectangle by $$$90$$$ degrees or leave it as it is. If you turn a rectangle, its width will be height, and its height will be width. Notice that you can turn any number of rectangles, you also can turn all or none of them. You can not change the order of the rectangles.Find out if there is a way to make the rectangles go in order of non-ascending height. In other words, after all the turns, a height of every rectangle has to be not greater than the height of the previous rectangle (if it is such). ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1097"You are given a sequence of integers of length $$$n$$$ and integer number $$$k$$$. You should print any integer number $$$x$$$ in the range of $$$[1; 10^9]$$$ (i.e. $$$1 \le x \le 10^9$$$) such that exactly $$$k$$$ elements of given sequence are less than or equal to $$$x$$$.Note that the sequence can contain equal elements.If there is no such $$$x$$$, print ""-1"" (without quotes).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1098"  This is an interactive taskWilliam has a certain sequence of integers $$$a_1, a_2, \dots, a_n$$$ in his mind, but due to security concerns, he does not want to reveal it to you completely. William is ready to respond to no more than $$$2 \cdot n$$$ of the following questions:  What is the result of a bitwise AND of two items with indices $$$i$$$ and $$$j$$$ ($$$i \neq j$$$)  What is the result of a bitwise OR of two items with indices $$$i$$$ and $$$j$$$ ($$$i \neq j$$$) You can ask William these questions and you need to find the $$$k$$$-th smallest number of the sequence.Formally the $$$k$$$-th smallest number is equal to the number at the $$$k$$$-th place in a 1-indexed array sorted in non-decreasing order. For example in array $$$[5, 3, 3, 10, 1]$$$ $$$4$$$th smallest number is equal to $$$5$$$, and $$$2$$$nd and $$$3$$$rd are $$$3$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1099"It turns out that the meaning of life is a permutation $$$p_1, p_2, \ldots, p_n$$$ of the integers $$$1, 2, \ldots, n$$$ ($$$2 \leq n \leq 100$$$). Omkar, having created all life, knows this permutation, and will allow you to figure it out using some queries.A query consists of an array $$$a_1, a_2, \ldots, a_n$$$ of integers between $$$1$$$ and $$$n$$$. $$$a$$$ is not required to be a permutation. Omkar will first compute the pairwise sum of $$$a$$$ and $$$p$$$, meaning that he will compute an array $$$s$$$ where $$$s_j = p_j + a_j$$$ for all $$$j = 1, 2, \ldots, n$$$. Then, he will find the smallest index $$$k$$$ such that $$$s_k$$$ occurs more than once in $$$s$$$, and answer with $$$k$$$. If there is no such index $$$k$$$, then he will answer with $$$0$$$.You can perform at most $$$2n$$$ queries. Figure out the meaning of life $$$p$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1100"Gildong has bought a famous painting software cfpaint. The working screen of cfpaint is square-shaped consisting of $$$n$$$ rows and $$$n$$$ columns of square cells. The rows are numbered from $$$1$$$ to $$$n$$$, from top to bottom, and the columns are numbered from $$$1$$$ to $$$n$$$, from left to right. The position of a cell at row $$$r$$$ and column $$$c$$$ is represented as $$$(r, c)$$$. There are only two colors for the cells in cfpaint — black and white.There is a tool named eraser in cfpaint. The eraser has an integer size $$$k$$$ ($$$1 \le k \le n$$$). To use the eraser, Gildong needs to click on a cell $$$(i, j)$$$ where $$$1 \le i, j \le n - k + 1$$$. When a cell $$$(i, j)$$$ is clicked, all of the cells $$$(i', j')$$$ where $$$i \le i' \le i + k - 1$$$ and $$$j \le j' \le j + k - 1$$$ become white. In other words, a square with side equal to $$$k$$$ cells and top left corner at $$$(i, j)$$$ is colored white.A white line is a row or a column without any black cells.Gildong has worked with cfpaint for some time, so some of the cells (possibly zero or all) are currently black. He wants to know the maximum number of white lines after using the eraser exactly once. Help Gildong find the answer to his question.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1101"Vasya has the square chessboard of size n × n and m rooks. Initially the chessboard is empty. Vasya will consequently put the rooks on the board one after another.The cell of the field is under rook's attack, if there is at least one rook located in the same row or in the same column with this cell. If there is a rook located in the cell, this cell is also under attack.You are given the positions of the board where Vasya will put rooks. For each rook you have to determine the number of cells which are not under attack after Vasya puts it on the board.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1102"Limak is a little polar bear. He likes nice strings — strings of length n, consisting of lowercase English letters only.The distance between two letters is defined as the difference between their positions in the alphabet. For example, , and .Also, the distance between two nice strings is defined as the sum of distances of corresponding letters. For example, , and .Limak gives you a nice string s and an integer k. He challenges you to find any nice string s' that . Find any s' satisfying the given conditions, or print ""-1"" if it's impossible to do so.As input/output can reach huge size it is recommended to use fast input/output methods: for example, prefer to use gets/scanf/printf instead of getline/cin/cout in C++, prefer to use BufferedReader/PrintWriter instead of Scanner/System.out in Java.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1103"Methodius received an email from his friend Polycarp. However, Polycarp's keyboard is broken, so pressing a key on it once may cause the corresponding symbol to appear more than once (if you press a key on a regular keyboard, it prints exactly one symbol).For example, as a result of typing the word ""hello"", the following words could be printed: ""hello"", ""hhhhello"", ""hheeeellllooo"", but the following could not be printed: ""hell"", ""helo"", ""hhllllooo"".Note, that when you press a key, the corresponding symbol must appear (possibly, more than once). The keyboard is broken in a random manner, it means that pressing the same key you can get the different number of letters in the result.For each word in the letter, Methodius has guessed what word Polycarp actually wanted to write, but he is not sure about it, so he asks you to help him.You are given a list of pairs of words. For each pair, determine if the second word could be printed by typing the first one on Polycarp's keyboard.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1104"The BFS algorithm is defined as follows.  Consider an undirected graph with vertices numbered from $$$1$$$ to $$$n$$$. Initialize $$$q$$$ as a new queue containing only vertex $$$1$$$, mark the vertex $$$1$$$ as used.  Extract a vertex $$$v$$$ from the head of the queue $$$q$$$.  Print the index of vertex $$$v$$$.  Iterate in arbitrary order through all such vertices $$$u$$$ that $$$u$$$ is a neighbor of $$$v$$$ and is not marked yet as used. Mark the vertex $$$u$$$ as used and insert it into the tail of the queue $$$q$$$.  If the queue is not empty, continue from step 2.  Otherwise finish. Since the order of choosing neighbors of each vertex can vary, it turns out that there may be multiple sequences which BFS can print.In this problem you need to check whether a given sequence corresponds to some valid BFS traversal of the given tree starting from vertex $$$1$$$. The tree is an undirected graph, such that there is exactly one simple path between any two vertices.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"1105"Two players decided to play one interesting card game.There is a deck of $$$n$$$ cards, with values from $$$1$$$ to $$$n$$$. The values of cards are pairwise different (this means that no two different cards have equal values). At the beginning of the game, the deck is completely distributed between players such that each player has at least one card. The game goes as follows: on each turn, each player chooses one of their cards (whichever they want) and puts on the table, so that the other player doesn't see which card they chose. After that, both cards are revealed, and the player, value of whose card was larger, takes both cards in his hand. Note that as all cards have different values, one of the cards will be strictly larger than the other one. Every card may be played any amount of times. The player loses if he doesn't have any cards.For example, suppose that $$$n = 5$$$, the first player has cards with values $$$2$$$ and $$$3$$$, and the second player has cards with values $$$1$$$, $$$4$$$, $$$5$$$. Then one possible flow of the game is:The first player chooses the card $$$3$$$. The second player chooses the card $$$1$$$. As $$$3>1$$$, the first player gets both cards. Now the first player has cards $$$1$$$, $$$2$$$, $$$3$$$, the second player has cards $$$4$$$, $$$5$$$.The first player chooses the card $$$3$$$. The second player chooses the card $$$4$$$. As $$$3<4$$$, the second player gets both cards. Now the first player has cards $$$1$$$, $$$2$$$. The second player has cards $$$3$$$, $$$4$$$, $$$5$$$.The first player chooses the card $$$1$$$. The second player chooses the card $$$3$$$. As $$$1<3$$$, the second player gets both cards. Now the first player has only the card $$$2$$$. The second player has cards $$$1$$$, $$$3$$$, $$$4$$$, $$$5$$$.The first player chooses the card $$$2$$$. The second player chooses the card $$$4$$$. As $$$2<4$$$, the second player gets both cards. Now the first player is out of cards and loses. Therefore, the second player wins.Who will win if both players are playing optimally? It can be shown that one of the players has a winning strategy.","['games', 'math']","[1, 0, 0, 1, 0, 0, 0, 0]"1106"A piece of paper contains an array of n integers a1, a2, ..., an. Your task is to find a number that occurs the maximum number of times in this array.However, before looking for such number, you are allowed to perform not more than k following operations — choose an arbitrary element from the array and add 1 to it. In other words, you are allowed to increase some array element by 1 no more than k times (you are allowed to increase the same element of the array multiple times).Your task is to find the maximum number of occurrences of some number in the array after performing no more than k allowed operations. If there are several such numbers, your task is to find the minimum one.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1107"You are given an array $$$a_1, a_2, \ldots, a_n$$$ of positive integers. A good pair is a pair of indices $$$(i, j)$$$ with $$$1 \leq i, j \leq n$$$ such that, for all $$$1 \leq k \leq n$$$, the following equality holds:$$$$$$ |a_i - a_k| + |a_k - a_j| = |a_i - a_j|, $$$$$$ where $$$|x|$$$ denotes the absolute value of $$$x$$$.Find a good pair. Note that $$$i$$$ can be equal to $$$j$$$.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1108"Vasya has got a magic matrix $$$a$$$ of size $$$n \times m$$$. The rows of the matrix are numbered from $$$1$$$ to $$$n$$$ from top to bottom, the columns are numbered from $$$1$$$ to $$$m$$$ from left to right. Let $$$a_{ij}$$$ be the element in the intersection of the $$$i$$$-th row and the $$$j$$$-th column.Vasya has also got a chip. Initially, the chip is in the intersection of the $$$r$$$-th row and the $$$c$$$-th column (that is, in the element $$$a_{rc}$$$). Vasya performs the following process as long as possible: among all elements of the matrix having their value less than the value of the element with the chip in it, Vasya randomly and equiprobably chooses one element and moves his chip to this element.After moving the chip, he adds to his score the square of the Euclidean distance between these elements (that is, between the element in which the chip is now and the element the chip was moved from). The process ends when there are no elements having their values less than the value of the element with the chip in it.Euclidean distance between matrix elements with coordinates $$$(i_1, j_1)$$$ and $$$(i_2, j_2)$$$ is equal to $$$\sqrt{(i_1-i_2)^2 + (j_1-j_2)^2}$$$.Calculate the expected value of the Vasya's final score.It can be shown that the answer can be represented as $$$\frac{P}{Q}$$$, where $$$P$$$ and $$$Q$$$ are coprime integer numbers, and $$$Q \not\equiv 0~(mod ~ 998244353)$$$. Print the value $$$P \cdot Q^{-1}$$$ modulo $$$998244353$$$.","['math', 'probabilities']","[0, 0, 0, 1, 0, 1, 0, 0]"1109"David was given a red checkered rectangle of size $$$n \times m$$$. But he doesn't like it. So David cuts the original or any other rectangle piece obtained during the cutting into two new pieces along the grid lines. He can do this operation as many times as he wants.As a result, he will get a set of rectangles. Rectangles $$$1 \times 1$$$ are forbidden.David also knows how to paint the cells blue. He wants each rectangle from the resulting set of pieces to be colored such that any pair of adjacent cells by side (from the same piece) have different colors.What is the minimum number of cells David will have to paint?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1110"You are given an array of n elements, you must make it a co-prime array in as few moves as possible.In each move you can insert any positive integral number you want not greater than 109 in any place in the array.An array is co-prime if any two adjacent numbers of it are co-prime.In the number theory, two integers a and b are said to be co-prime if the only positive integer that divides both of them is 1.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1111"You are playing a game of Jongmah. You don't need to know the rules to solve this problem. You have $$$n$$$ tiles in your hand. Each tile has an integer between $$$1$$$ and $$$m$$$ written on it.To win the game, you will need to form some number of triples. Each triple consists of three tiles, such that the numbers written on the tiles are either all the same or consecutive. For example, $$$7, 7, 7$$$ is a valid triple, and so is $$$12, 13, 14$$$, but $$$2,2,3$$$ or $$$2,4,6$$$ are not. You can only use the tiles in your hand to form triples. Each tile can be used in at most one triple.To determine how close you are to the win, you want to know the maximum number of triples you can form from the tiles in your hand.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1112"Given an array $$$a=[a_1,a_2,\dots,a_n]$$$ of $$$n$$$ positive integers, you can do operations of two types on it:  Add $$$1$$$ to every element with an odd index. In other words change the array as follows: $$$a_1 := a_1 +1, a_3 := a_3 + 1, a_5 := a_5+1, \dots$$$.  Add $$$1$$$ to every element with an even index. In other words change the array as follows: $$$a_2 := a_2 +1, a_4 := a_4 + 1, a_6 := a_6+1, \dots$$$.Determine if after any number of operations it is possible to make the final array contain only even numbers or only odd numbers. In other words, determine if you can make all elements of the array have the same parity after any number of operations.Note that you can do operations of both types any number of times (even none). Operations of different types can be performed a different number of times.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1113"Let's introduce a number system which is based on a roman digits. There are digits I, V, X, L which correspond to the numbers $$$1$$$, $$$5$$$, $$$10$$$ and $$$50$$$ respectively. The use of other roman digits is not allowed.Numbers in this system are written as a sequence of one or more digits. We define the value of the sequence simply as the sum of digits in it.For example, the number XXXV evaluates to $$$35$$$ and the number IXI — to $$$12$$$.Pay attention to the difference to the traditional roman system — in our system any sequence of digits is valid, moreover the order of digits doesn't matter, for example IX means $$$11$$$, not $$$9$$$.One can notice that this system is ambiguous, and some numbers can be written in many different ways. Your goal is to determine how many distinct integers can be represented by exactly $$$n$$$ roman digits I, V, X, L.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1114"Being tired of participating in too many Codeforces rounds, Gildong decided to take some rest in a park. He sat down on a bench, and soon he found two rabbits hopping around. One of the rabbits was taller than the other.He noticed that the two rabbits were hopping towards each other. The positions of the two rabbits can be represented as integer coordinates on a horizontal line. The taller rabbit is currently on position $$$x$$$, and the shorter rabbit is currently on position $$$y$$$ ($$$x \lt y$$$). Every second, each rabbit hops to another position. The taller rabbit hops to the positive direction by $$$a$$$, and the shorter rabbit hops to the negative direction by $$$b$$$.  For example, let's say $$$x=0$$$, $$$y=10$$$, $$$a=2$$$, and $$$b=3$$$. At the $$$1$$$-st second, each rabbit will be at position $$$2$$$ and $$$7$$$. At the $$$2$$$-nd second, both rabbits will be at position $$$4$$$.Gildong is now wondering: Will the two rabbits be at the same position at the same moment? If so, how long will it take? Let's find a moment in time (in seconds) after which the rabbits will be at the same point.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1115"Eugeny has array a = a1, a2, ..., an, consisting of n integers. Each integer ai equals to -1, or to 1. Also, he has m queries:  Query number i is given as a pair of integers li, ri (1 ≤ li ≤ ri ≤ n).  The response to the query will be integer 1, if the elements of array a can be rearranged so as the sum ali + ali + 1 + ... + ari = 0, otherwise the response to the query will be integer 0. Help Eugeny, answer all his queries.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1116"You are given a matrix with $$$n$$$ rows (numbered from $$$1$$$ to $$$n$$$) and $$$m$$$ columns (numbered from $$$1$$$ to $$$m$$$). A number $$$a_{i, j}$$$ is written in the cell belonging to the $$$i$$$-th row and the $$$j$$$-th column, each number is either $$$0$$$ or $$$1$$$.A chip is initially in the cell $$$(1, 1)$$$, and it will be moved to the cell $$$(n, m)$$$. During each move, it either moves to the next cell in the current row, or in the current column (if the current cell is $$$(x, y)$$$, then after the move it can be either $$$(x + 1, y)$$$ or $$$(x, y + 1)$$$). The chip cannot leave the matrix.Consider each path of the chip from $$$(1, 1)$$$ to $$$(n, m)$$$. A path is called palindromic if the number in the first cell is equal to the number in the last cell, the number in the second cell is equal to the number in the second-to-last cell, and so on.Your goal is to change the values in the minimum number of cells so that every path is palindromic.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1117"The crowdedness of the discotheque would never stop our friends from having fun, but a bit more spaciousness won't hurt, will it?The discotheque can be seen as an infinite xy-plane, in which there are a total of n dancers. Once someone starts moving around, they will move only inside their own movement range, which is a circular area Ci described by a center (xi, yi) and a radius ri. No two ranges' borders have more than one common point, that is for every pair (i, j) (1 ≤ i < j ≤ n) either ranges Ci and Cj are disjoint, or one of them is a subset of the other. Note that it's possible that two ranges' borders share a single common point, but no two dancers have exactly the same ranges.Tsukihi, being one of them, defines the spaciousness to be the area covered by an odd number of movement ranges of dancers who are moving. An example is shown below, with shaded regions representing the spaciousness if everyone moves at the same time.  But no one keeps moving for the whole night after all, so the whole night's time is divided into two halves — before midnight and after midnight. Every dancer moves around in one half, while sitting down with friends in the other. The spaciousness of two halves are calculated separately and their sum should, of course, be as large as possible. The following figure shows an optimal solution to the example above.  By different plans of who dances in the first half and who does in the other, different sums of spaciousness over two halves are achieved. You are to find the largest achievable value of this sum.","['geometry', 'trees']","[0, 1, 0, 0, 0, 0, 0, 1]"1118"Let's call a list of positive integers $$$a_0, a_1, ..., a_{n-1}$$$ a power sequence if there is a positive integer $$$c$$$, so that for every $$$0 \le i \le n-1$$$ then $$$a_i = c^i$$$.Given a list of $$$n$$$ positive integers $$$a_0, a_1, ..., a_{n-1}$$$, you are allowed to:  Reorder the list (i.e. pick a permutation $$$p$$$ of $$$\{0,1,...,n - 1\}$$$ and change $$$a_i$$$ to $$$a_{p_i}$$$), then  Do the following operation any number of times: pick an index $$$i$$$ and change $$$a_i$$$ to $$$a_i - 1$$$ or $$$a_i + 1$$$ (i.e. increment or decrement $$$a_i$$$ by $$$1$$$) with a cost of $$$1$$$. Find the minimum cost to transform $$$a_0, a_1, ..., a_{n-1}$$$ into a power sequence.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1119"You are given an undirected graph consisting of $$$n$$$ vertices and $$$n$$$ edges. It is guaranteed that the given graph is connected (i. e. it is possible to reach any vertex from any other vertex) and there are no self-loops and multiple edges in the graph.Your task is to calculate the number of simple paths of length at least $$$1$$$ in the given graph. Note that paths that differ only by their direction are considered the same (i. e. you have to calculate the number of undirected paths). For example, paths $$$[1, 2, 3]$$$ and $$$[3, 2, 1]$$$ are considered the same.You have to answer $$$t$$$ independent test cases.Recall that a path in the graph is a sequence of vertices $$$v_1, v_2, \ldots, v_k$$$ such that each pair of adjacent (consecutive) vertices in this sequence is connected by an edge. The length of the path is the number of edges in it. A simple path is such a path that all vertices in it are distinct.","['graphs', 'trees']","[0, 0, 1, 0, 0, 0, 0, 1]"1120"Little Petya likes arrays that consist of non-negative integers a lot. Recently his mom has presented him one such array consisting of n elements. Petya immediately decided to find there a segment of consecutive elements, such that the xor of all numbers from this segment was maximal possible. Help him with that.The xor operation is the bitwise exclusive ""OR"", that is denoted as ""xor"" in Pascal and ""^"" in C/C++/Java.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1121"You've got a robot, its task is destroying bombs on a square plane. Specifically, the square plane contains n bombs, the i-th bomb is at point with coordinates (xi, yi). We know that no two bombs are at the same point and that no bomb is at point with coordinates (0, 0). Initially, the robot is at point with coordinates (0, 0). Also, let's mark the robot's current position as (x, y). In order to destroy all the bombs, the robot can perform three types of operations:  Operation has format ""1 k dir"". To perform the operation robot have to move in direction dir k (k ≥ 1) times. There are only 4 directions the robot can move in: ""R"", ""L"", ""U"", ""D"". During one move the robot can move from the current point to one of following points: (x + 1, y), (x - 1, y), (x, y + 1), (x, y - 1) (corresponding to directions). It is forbidden to move from point (x, y), if at least one point on the path (besides the destination point) contains a bomb.  Operation has format ""2"". To perform the operation robot have to pick a bomb at point (x, y) and put it in a special container. Thus, the robot can carry the bomb from any point to any other point. The operation cannot be performed if point (x, y) has no bomb. It is forbidden to pick a bomb if the robot already has a bomb in its container.  Operation has format ""3"". To perform the operation robot have to take a bomb out of the container and destroy it. You are allowed to perform this operation only if the robot is at point (0, 0). It is forbidden to perform the operation if the container has no bomb. Help the robot and find the shortest possible sequence of operations he can perform to destroy all bombs on the coordinate plane.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1122"Captain Marmot wants to prepare a huge and important battle against his enemy, Captain Snake. For this battle he has n regiments, each consisting of 4 moles.Initially, each mole i (1 ≤ i ≤ 4n) is placed at some position (xi, yi) in the Cartesian plane. Captain Marmot wants to move some moles to make the regiments compact, if it's possible.Each mole i has a home placed at the position (ai, bi). Moving this mole one time means rotating his position point (xi, yi) 90 degrees counter-clockwise around it's home point (ai, bi).A regiment is compact only if the position points of the 4 moles form a square with non-zero area.Help Captain Marmot to find out for each regiment the minimal number of moves required to make that regiment compact, if it's possible.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"1123"The city where Mocha lives in is called Zhijiang. There are $$$n+1$$$ villages and $$$2n-1$$$ directed roads in this city. There are two kinds of roads:  $$$n-1$$$ roads are from village $$$i$$$ to village $$$i+1$$$, for all $$$1\leq i \leq n-1$$$.  $$$n$$$ roads can be described by a sequence $$$a_1,\ldots,a_n$$$. If $$$a_i=0$$$, the $$$i$$$-th of these roads goes from village $$$i$$$ to village $$$n+1$$$, otherwise it goes from village $$$n+1$$$ to village $$$i$$$, for all $$$1\leq i\leq n$$$. Mocha plans to go hiking with Taki this weekend. To avoid the trip being boring, they plan to go through every village exactly once. They can start and finish at any villages. Can you help them to draw up a plan? ",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"1124"This is the hard version of the problem. The difference between the versions is that in the easy version all prices $$$a_i$$$ are different. You can make hacks if and only if you solved both versions of the problem.Today is Sage's birthday, and she will go shopping to buy ice spheres. All $$$n$$$ ice spheres are placed in a row and they are numbered from $$$1$$$ to $$$n$$$ from left to right. Each ice sphere has a positive integer price. In this version, some prices can be equal.An ice sphere is cheap if it costs strictly less than two neighboring ice spheres: the nearest to the left and the nearest to the right. The leftmost and the rightmost ice spheres are not cheap. Sage will choose all cheap ice spheres and then buy only them.You can visit the shop before Sage and reorder the ice spheres as you wish. Find out the maximum number of ice spheres that Sage can buy, and show how the ice spheres should be reordered.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1125"Ghosts live in harmony and peace, they travel the space without any purpose other than scare whoever stands in their way.There are $$$n$$$ ghosts in the universe, they move in the $$$OXY$$$ plane, each one of them has its own velocity that does not change in time: $$$\overrightarrow{V} = V_{x}\overrightarrow{i} + V_{y}\overrightarrow{j}$$$ where $$$V_{x}$$$ is its speed on the $$$x$$$-axis and $$$V_{y}$$$ is on the $$$y$$$-axis.A ghost $$$i$$$ has experience value $$$EX_i$$$, which represent how many ghosts tried to scare him in his past. Two ghosts scare each other if they were in the same cartesian point at a moment of time.As the ghosts move with constant speed, after some moment of time there will be no further scaring (what a relief!) and the experience of ghost kind $$$GX = \sum_{i=1}^{n} EX_i$$$ will never increase.Tameem is a red giant, he took a picture of the cartesian plane at a certain moment of time $$$T$$$, and magically all the ghosts were aligned on a line of the form $$$y = a \cdot x + b$$$. You have to compute what will be the experience index of the ghost kind $$$GX$$$ in the indefinite future, this is your task for today.Note that when Tameem took the picture, $$$GX$$$ may already be greater than $$$0$$$, because many ghosts may have scared one another at any moment between $$$[-\infty, T]$$$.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"1126"In fact, the problems E1 and E2 do not have much in common. You should probably think of them as two separate problems.You are given an integer array $$$a[1 \ldots n] = [a_1, a_2, \ldots, a_n]$$$.Let us consider an empty deque (double-ended queue). A deque is a data structure that supports adding elements to both the beginning and the end. So, if there are elements $$$[3, 4, 4]$$$ currently in the deque, adding an element $$$1$$$ to the beginning will produce the sequence $$$[\color{red}{1}, 3, 4, 4]$$$, and adding the same element to the end will produce $$$[3, 4, 4, \color{red}{1}]$$$.The elements of the array are sequentially added to the initially empty deque, starting with $$$a_1$$$ and finishing with $$$a_n$$$. Before adding each element to the deque, you may choose whether to add it to the beginning or to the end.For example, if we consider an array $$$a = [3, 7, 5, 5]$$$, one of the possible sequences of actions looks like this: $$$\quad$$$ 1.add $$$3$$$ to the beginning of the deque:deque has a sequence $$$[\color{red}{3}]$$$ in it;$$$\quad$$$ 2.add $$$7$$$ to the end of the deque:deque has a sequence $$$[3, \color{red}{7}]$$$ in it;$$$\quad$$$ 3.add $$$5$$$ to the end of the deque:deque has a sequence $$$[3, 7, \color{red}{5}]$$$ in it;$$$\quad$$$ 4.add $$$5$$$ to the beginning of the deque:deque has a sequence $$$[\color{red}{5}, 3, 7, 5]$$$ in it;Find the minimal possible number of inversions in the deque after the whole array is processed. An inversion in sequence $$$d$$$ is a pair of indices $$$(i, j)$$$ such that $$$i < j$$$ and $$$d_i > d_j$$$. For example, the array $$$d = [5, 3, 7, 5]$$$ has exactly two inversions — $$$(1, 2)$$$ and $$$(3, 4)$$$, since $$$d_1 = 5 > 3 = d_2$$$ and $$$d_3 = 7 > 5 = d_4$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1127"You desperately need to build some string t. For that you've got n more strings s1, s2, ..., sn. To build string t, you are allowed to perform exactly |t| (|t| is the length of string t) operations on these strings. Each operation looks like that:  choose any non-empty string from strings s1, s2, ..., sn;  choose an arbitrary character from the chosen string and write it on a piece of paper;  remove the chosen character from the chosen string. Note that after you perform the described operation, the total number of characters in strings s1, s2, ..., sn decreases by 1. We are assumed to build string t, if the characters, written on the piece of paper, in the order of performed operations form string t.There are other limitations, though. For each string si you know number ai — the maximum number of characters you are allowed to delete from string si. You also know that each operation that results in deleting a character from string si, costs i rubles. That is, an operation on string s1 is the cheapest (it costs 1 ruble), and the operation on string sn is the most expensive one (it costs n rubles).Your task is to count the minimum amount of money (in rubles) you will need to build string t by the given rules. Consider the cost of building string t to be the sum of prices of the operations you use.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"1128"There are n employees in Alternative Cake Manufacturing (ACM). They are now voting on some very important question and the leading world media are trying to predict the outcome of the vote.Each of the employees belongs to one of two fractions: depublicans or remocrats, and these two fractions have opposite opinions on what should be the outcome of the vote. The voting procedure is rather complicated:   Each of n employees makes a statement. They make statements one by one starting from employees 1 and finishing with employee n. If at the moment when it's time for the i-th employee to make a statement he no longer has the right to vote, he just skips his turn (and no longer takes part in this voting).  When employee makes a statement, he can do nothing or declare that one of the other employees no longer has a right to vote. It's allowed to deny from voting people who already made the statement or people who are only waiting to do so. If someone is denied from voting he no longer participates in the voting till the very end.  When all employees are done with their statements, the procedure repeats: again, each employees starting from 1 and finishing with n who are still eligible to vote make their statements.  The process repeats until there is only one employee eligible to vote remaining and he determines the outcome of the whole voting. Of course, he votes for the decision suitable for his fraction. You know the order employees are going to vote and that they behave optimal (and they also know the order and who belongs to which fraction). Predict the outcome of the vote.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1129"A string is called diverse if it contains consecutive (adjacent) letters of the Latin alphabet and each letter occurs exactly once. For example, the following strings are diverse: ""fced"", ""xyz"", ""r"" and ""dabcef"". The following string are not diverse: ""az"", ""aa"", ""bad"" and ""babc"". Note that the letters 'a' and 'z' are not adjacent.Formally, consider positions of all letters in the string in the alphabet. These positions should form contiguous segment, i.e. they should come one by one without any gaps. And all letters in the string should be distinct (duplicates are not allowed).You are given a sequence of strings. For each string, if it is diverse, print ""Yes"". Otherwise, print ""No"".",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1130"You are given the following points with integer coordinates on the plane: M0, A0, A1, ..., An - 1, where n is odd number. Now we define the following infinite sequence of points Mi: Mi is symmetric to Mi - 1 according  (for every natural number i). Here point B is symmetric to A according M, if M is the center of the line segment AB. Given index j find the point Mj.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"1131"This time the Berland Team Olympiad in Informatics is held in a remote city that can only be reached by one small bus. Bus has n passenger seats, seat i can be occupied only by a participant from the city ai.Today the bus has completed m trips, each time bringing n participants. The participants were then aligned in one line in the order they arrived, with people from the same bus standing in the order of their seats (i. e. if we write down the cities where the participants came from, we get the sequence a1, a2, ..., an repeated m times).After that some teams were formed, each consisting of k participants form the same city standing next to each other in the line. Once formed, teams left the line. The teams were formed until there were no k neighboring participants from the same city.Help the organizers determine how many participants have left in the line after that process ended. We can prove that answer doesn't depend on the order in which teams were selected.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1132"There is an array $$$a$$$ of $$$2^{30}$$$ integers, indexed from $$$0$$$ to $$$2^{30}-1$$$. Initially, you know that $$$0 \leq a_i < 2^{30}$$$ ($$$0 \leq i < 2^{30}$$$), but you do not know any of the values. Your task is to process queries of two types: 1 l r x: You are informed that the bitwise xor of the subarray $$$[l, r]$$$ (ends inclusive) is equal to $$$x$$$. That is, $$$a_l \oplus a_{l+1} \oplus \ldots \oplus a_{r-1} \oplus a_r = x$$$, where $$$\oplus$$$ is the bitwise xor operator. In some cases, the received update contradicts past updates. In this case, you should ignore the contradicting update (the current update). 2 l r: You are asked to output the bitwise xor of the subarray $$$[l, r]$$$ (ends inclusive). If it is still impossible to know this value, considering all past updates, then output $$$-1$$$.Note that the queries are encoded. That is, you need to write an online solution.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1133"You are given two strings of equal length $$$s$$$ and $$$t$$$ consisting of lowercase Latin letters. You may perform any number (possibly, zero) operations on these strings.During each operation you choose two adjacent characters in any string and assign the value of the first character to the value of the second or vice versa.For example, if $$$s$$$ is ""acbc"" you can get the following strings in one operation:   ""aabc"" (if you perform $$$s_2 = s_1$$$);  ""ccbc"" (if you perform $$$s_1 = s_2$$$);  ""accc"" (if you perform $$$s_3 = s_2$$$ or $$$s_3 = s_4$$$);  ""abbc"" (if you perform $$$s_2 = s_3$$$);  ""acbb"" (if you perform $$$s_4 = s_3$$$); Note that you can also apply this operation to the string $$$t$$$.Please determine whether it is possible to transform $$$s$$$ into $$$t$$$, applying the operation above any number of times.Note that you have to answer $$$q$$$ independent queries.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1134"One tradition of ACM-ICPC contests is that a team gets a balloon for every solved problem. We assume that the submission time doesn't matter and teams are sorted only by the number of balloons they have. It means that one's place is equal to the number of teams with more balloons, increased by 1. For example, if there are seven teams with more balloons, you get the eight place. Ties are allowed.You should know that it's important to eat before a contest. If the number of balloons of a team is greater than the weight of this team, the team starts to float in the air together with their workstation. They eventually touch the ceiling, what is strictly forbidden by the rules. The team is then disqualified and isn't considered in the standings.A contest has just finished. There are n teams, numbered 1 through n. The i-th team has ti balloons and weight wi. It's guaranteed that ti doesn't exceed wi so nobody floats initially.Limak is a member of the first team. He doesn't like cheating and he would never steal balloons from other teams. Instead, he can give his balloons away to other teams, possibly making them float. Limak can give away zero or more balloons of his team. Obviously, he can't give away more balloons than his team initially has.What is the best place Limak can get?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1135"You are given an array a with n elements. Each element of a is either 0 or 1.Let's denote the length of the longest subsegment of consecutive elements in a, consisting of only numbers one, as f(a). You can change no more than k zeroes to ones to maximize f(a).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1136Vasya has a graph containing both directed (oriented) and undirected (non-oriented) edges. There can be multiple edges between a pair of vertices.Vasya has picked a vertex s from the graph. Now Vasya wants to create two separate plans:  to orient each undirected edge in one of two possible directions to maximize number of vertices reachable from vertex s;  to orient each undirected edge in one of two possible directions to minimize number of vertices reachable from vertex s. In each of two plans each undirected edge must become directed. For an edge chosen directions can differ in two plans.Help Vasya find the plans.,['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"1137"You are given three strings (s1, s2, s3). For each integer l (1 ≤ l ≤ min(|s1|, |s2|, |s3|) you need to find how many triples (i1, i2, i3) exist such that three strings sk[ik... ik + l - 1] (k = 1, 2, 3) are pairwise equal. Print all found numbers modulo 1000000007 (109 + 7).See notes if you are not sure about some of the denotions used in the statement.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1138"Vasya has several phone books, in which he recorded the telephone numbers of his friends. Each of his friends can have one or several phone numbers.Vasya decided to organize information about the phone numbers of friends. You will be given n strings — all entries from Vasya's phone books. Each entry starts with a friend's name. Then follows the number of phone numbers in the current entry, and then the phone numbers themselves. It is possible that several identical phones are recorded in the same record.Vasya also believes that if the phone number a is a suffix of the phone number b (that is, the number b ends up with a), and both numbers are written by Vasya as the phone numbers of the same person, then a is recorded without the city code and it should not be taken into account.The task is to print organized information about the phone numbers of Vasya's friends. It is possible that two different people have the same number. If one person has two numbers x and y, and x is a suffix of y (that is, y ends in x), then you shouldn't print number x. If the number of a friend in the Vasya's phone books is recorded several times in the same format, it is necessary to take it into account exactly once.Read the examples to understand statement and format of the output better.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1139"You are given a matrix $$$a$$$ consisting of positive integers. It has $$$n$$$ rows and $$$m$$$ columns.Construct a matrix $$$b$$$ consisting of positive integers. It should have the same size as $$$a$$$, and the following conditions should be met:   $$$1 \le b_{i,j} \le 10^6$$$;  $$$b_{i,j}$$$ is a multiple of $$$a_{i,j}$$$;  the absolute value of the difference between numbers in any adjacent pair of cells (two cells that share the same side) in $$$b$$$ is equal to $$$k^4$$$ for some integer $$$k \ge 1$$$ ($$$k$$$ is not necessarily the same for all pairs, it is own for each pair). We can show that the answer always exists.","['graphs', 'math', 'number theory']","[0, 0, 1, 1, 1, 0, 0, 0]"1140"You are playing a very popular game called Cubecraft. Initially, you have one stick and want to craft $$$k$$$ torches. One torch can be crafted using one stick and one coal.Hopefully, you've met a very handsome wandering trader who has two trade offers:  exchange $$$1$$$ stick for $$$x$$$ sticks (you lose $$$1$$$ stick and gain $$$x$$$ sticks).  exchange $$$y$$$ sticks for $$$1$$$ coal (you lose $$$y$$$ sticks and gain $$$1$$$ coal). During one trade, you can use only one of these two trade offers. You can use each trade offer any number of times you want to, in any order.Your task is to find the minimum number of trades you need to craft at least $$$k$$$ torches. The answer always exists under the given constraints.You have to answer $$$t$$$ independent test cases.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1141"Turbulent times are coming, so you decided to buy sugar in advance. There are $$$n$$$ shops around that sell sugar: the $$$i$$$-th shop sells one pack of sugar for $$$a_i$$$ coins, but only one pack to one customer each day. So in order to buy several packs, you need to visit several shops.Another problem is that prices are increasing each day: during the first day the cost is $$$a_i$$$, during the second day cost is $$$a_i + 1$$$, during the third day — $$$a_i + 2$$$ and so on for each shop $$$i$$$.On the contrary, your everyday budget is only $$$x$$$ coins. In other words, each day you go and buy as many packs as possible with total cost not exceeding $$$x$$$. Note that if you don't spend some amount of coins during a day, you can't use these coins during the next days.Eventually, the cost for each pack will exceed $$$x$$$, and you won't be able to buy even a single pack. So, how many packs will you be able to buy till that moment in total?",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1142"You are given an array $$$d_1, d_2, \dots, d_n$$$ consisting of $$$n$$$ integer numbers.Your task is to split this array into three parts (some of which may be empty) in such a way that each element of the array belongs to exactly one of the three parts, and each of the parts forms a consecutive contiguous subsegment (possibly, empty) of the original array. Let the sum of elements of the first part be $$$sum_1$$$, the sum of elements of the second part be $$$sum_2$$$ and the sum of elements of the third part be $$$sum_3$$$. Among all possible ways to split the array you have to choose a way such that $$$sum_1 = sum_3$$$ and $$$sum_1$$$ is maximum possible.More formally, if the first part of the array contains $$$a$$$ elements, the second part of the array contains $$$b$$$ elements and the third part contains $$$c$$$ elements, then:$$$$$$sum_1 = \sum\limits_{1 \le i \le a}d_i,$$$$$$ $$$$$$sum_2 = \sum\limits_{a + 1 \le i \le a + b}d_i,$$$$$$ $$$$$$sum_3 = \sum\limits_{a + b + 1 \le i \le a + b + c}d_i.$$$$$$The sum of an empty array is $$$0$$$.Your task is to find a way to split the array such that $$$sum_1 = sum_3$$$ and $$$sum_1$$$ is maximum possible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1143"There is unrest in the Galactic Senate. Several thousand solar systems have declared their intentions to leave the Republic. Master Heidi needs to select the Jedi Knights who will go on peacekeeping missions throughout the galaxy. It is well-known that the success of any peacekeeping mission depends on the colors of the lightsabers of the Jedi who will go on that mission. Heidi has n Jedi Knights standing in front of her, each one with a lightsaber of one of m possible colors. She knows that for the mission to be the most effective, she needs to select some contiguous interval of knights such that there are exactly k1 knights with lightsabers of the first color, k2 knights with lightsabers of the second color, ..., km knights with lightsabers of the m-th color.However, since the last time, she has learned that it is not always possible to select such an interval. Therefore, she decided to ask some Jedi Knights to go on an indefinite unpaid vacation leave near certain pits on Tatooine, if you know what I mean. Help Heidi decide what is the minimum number of Jedi Knights that need to be let go before she is able to select the desired interval from the subsequence of remaining knights.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1144"Vasya participates in a ski race along the X axis. The start is at point 0, and the finish is at L, that is, at a distance L meters from the start in the positive direction of the axis. Vasya has been training so hard that he can run one meter in exactly one second.Besides, there are n take-off ramps on the track, each ramp is characterized by four numbers:   xi represents the ramp's coordinate  di represents from how many meters Vasya will land if he goes down this ramp  ti represents the flight time in seconds  pi is the number, indicating for how many meters Vasya should gather speed to get ready and fly off the ramp. As Vasya gathers speed, he should ski on the snow (that is, he should not be flying), but his speed still equals one meter per second. Vasya is allowed to move in any direction on the X axis, but he is prohibited to cross the start line, that is go to the negative semiaxis. Vasya himself chooses which take-off ramps he will use and in what order, that is, he is not obliged to take off from all the ramps he encounters. Specifically, Vasya can skip the ramp. It is guaranteed that xi + di ≤ L, that is, Vasya cannot cross the finish line in flight.Vasya can jump from the ramp only in the positive direction of X axis. More formally, when using the i-th ramp, Vasya starts gathering speed at point xi - pi, jumps at point xi, and lands at point xi + di. He cannot use the ramp in opposite direction.Your task is to find the minimum time that Vasya will spend to cover the distance.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"1145"You have n devices that you want to use simultaneously.The i-th device uses ai units of power per second. This usage is continuous. That is, in λ seconds, the device will use λ·ai units of power. The i-th device currently has bi units of power stored. All devices can store an arbitrary amount of power.You have a single charger that can plug to any single device. The charger will add p units of power per second to a device. This charging is continuous. That is, if you plug in a device for λ seconds, it will gain λ·p units of power. You can switch which device is charging at any arbitrary unit of time (including real numbers), and the time it takes to switch is negligible.You are wondering, what is the maximum amount of time you can use the devices until one of them hits 0 units of power.If you can use the devices indefinitely, print -1. Otherwise, print the maximum amount of time before any one device hits 0 power.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1146"Given an integer $$$n$$$, find the maximum value of integer $$$k$$$ such that the following condition holds:  $$$n$$$ & ($$$n-1$$$) & ($$$n-2$$$) & ($$$n-3$$$) & ... ($$$k$$$) = $$$0$$$  where & denotes the bitwise AND operation.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1147"Madeline has an array $$$a$$$ of $$$n$$$ integers. A pair $$$(u, v)$$$ of integers forms an inversion in $$$a$$$ if:  $$$1 \le u < v \le n$$$.  $$$a_u > a_v$$$. Madeline recently found a magical paper, which allows her to write two indices $$$u$$$ and $$$v$$$ and swap the values $$$a_u$$$ and $$$a_v$$$. Being bored, she decided to write a list of pairs $$$(u_i, v_i)$$$ with the following conditions:  all the pairs in the list are distinct and form an inversion in $$$a$$$.  all the pairs that form an inversion in $$$a$$$ are in the list.  Starting from the given array, if you swap the values at indices $$$u_1$$$ and $$$v_1$$$, then the values at indices $$$u_2$$$ and $$$v_2$$$ and so on, then after all pairs are processed, the array $$$a$$$ will be sorted in non-decreasing order. Construct such a list or determine that no such list exists. If there are multiple possible answers, you may find any of them.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1148"ZS the Coder is playing a game. There is a number displayed on the screen and there are two buttons, ' + ' (plus) and '' (square root). Initially, the number 2 is displayed on the screen. There are n + 1 levels in the game and ZS the Coder start at the level 1.When ZS the Coder is at level k, he can :  Press the ' + ' button. This increases the number on the screen by exactly k. So, if the number on the screen was x, it becomes x + k. Press the '' button. Let the number on the screen be x. After pressing this button, the number becomes . After that, ZS the Coder levels up, so his current level becomes k + 1. This button can only be pressed when x is a perfect square, i.e. x = m2 for some positive integer m. Additionally, after each move, if ZS the Coder is at level k, and the number on the screen is m, then m must be a multiple of k. Note that this condition is only checked after performing the press. For example, if ZS the Coder is at level 4 and current number is 100, he presses the '' button and the number turns into 10. Note that at this moment, 10 is not divisible by 4, but this press is still valid, because after it, ZS the Coder is at level 5, and 10 is divisible by 5.ZS the Coder needs your help in beating the game — he wants to reach level n + 1. In other words, he needs to press the '' button n times. Help him determine the number of times he should press the ' + ' button before pressing the '' button at each level. Please note that ZS the Coder wants to find just any sequence of presses allowing him to reach level n + 1, but not necessarily a sequence minimizing the number of presses.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1149"CQXYM found a rectangle $$$A$$$ of size $$$n \times m$$$. There are $$$n$$$ rows and $$$m$$$ columns of blocks. Each block of the rectangle is an obsidian block or empty. CQXYM can change an obsidian block to an empty block or an empty block to an obsidian block in one operation.A rectangle $$$M$$$ size of $$$a \times b$$$ is called a portal if and only if it satisfies the following conditions:  $$$a \geq 5,b \geq 4$$$.  For all $$$1 < x < a$$$, blocks $$$M_{x,1}$$$ and $$$M_{x,b}$$$ are obsidian blocks.  For all $$$1 < x < b$$$, blocks $$$M_{1,x}$$$ and $$$M_{a,x}$$$ are obsidian blocks.  For all $$$1<x<a,1<y<b$$$, block $$$M_{x,y}$$$ is an empty block.  $$$M_{1, 1}, M_{1, b}, M_{a, 1}, M_{a, b}$$$ can be any type.  Note that the there must be $$$a$$$ rows and $$$b$$$ columns, not $$$b$$$ rows and $$$a$$$ columns.Note that corners can be any typeCQXYM wants to know the minimum number of operations he needs to make at least one sub-rectangle a portal.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1150"A string is called square if it is some string written twice in a row. For example, the strings ""aa"", ""abcabc"", ""abab"" and ""baabaa"" are square. But the strings ""aaa"", ""abaaab"" and ""abcdabc"" are not square.For a given string $$$s$$$ determine if it is square.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1151"Vasya is studying in the last class of school and soon he will take exams. He decided to study polynomials. Polynomial is a function P(x) = a0 + a1x1 + ... + anxn. Numbers ai are called coefficients of a polynomial, non-negative integer n is called a degree of a polynomial.Vasya has made a bet with his friends that he can solve any problem with polynomials. They suggested him the problem: ""Determine how many polynomials P(x) exist with integer non-negative coefficients so that , and , where  and b are given positive integers""? Vasya does not like losing bets, but he has no idea how to solve this task, so please help him to solve the problem.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1152"Orac is studying number theory, and he is interested in the properties of divisors.For two positive integers $$$a$$$ and $$$b$$$, $$$a$$$ is a divisor of $$$b$$$ if and only if there exists an integer $$$c$$$, such that $$$a\cdot c=b$$$.For $$$n \ge 2$$$, we will denote as $$$f(n)$$$ the smallest positive divisor of $$$n$$$, except $$$1$$$.For example, $$$f(7)=7,f(10)=2,f(35)=5$$$.For the fixed integer $$$n$$$, Orac decided to add $$$f(n)$$$ to $$$n$$$. For example, if he had an integer $$$n=5$$$, the new value of $$$n$$$ will be equal to $$$10$$$. And if he had an integer $$$n=6$$$, $$$n$$$ will be changed to $$$8$$$.Orac loved it so much, so he decided to repeat this operation several times.Now, for two positive integers $$$n$$$ and $$$k$$$, Orac asked you to add $$$f(n)$$$ to $$$n$$$ exactly $$$k$$$ times (note that $$$n$$$ will change after each operation, so $$$f(n)$$$ may change too) and tell him the final value of $$$n$$$.For example, if Orac gives you $$$n=5$$$ and $$$k=2$$$, at first you should add $$$f(5)=5$$$ to $$$n=5$$$, so your new value of $$$n$$$ will be equal to $$$n=10$$$, after that, you should add $$$f(10)=2$$$ to $$$10$$$, so your new (and the final!) value of $$$n$$$ will be equal to $$$12$$$.Orac may ask you these queries many times.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1153"You are given a long decimal number $$$a$$$ consisting of $$$n$$$ digits from $$$1$$$ to $$$9$$$. You also have a function $$$f$$$ that maps every digit from $$$1$$$ to $$$9$$$ to some (possibly the same) digit from $$$1$$$ to $$$9$$$.You can perform the following operation no more than once: choose a non-empty contiguous subsegment of digits in $$$a$$$, and replace each digit $$$x$$$ from this segment with $$$f(x)$$$. For example, if $$$a = 1337$$$, $$$f(1) = 1$$$, $$$f(3) = 5$$$, $$$f(7) = 3$$$, and you choose the segment consisting of three rightmost digits, you get $$$1553$$$ as the result.What is the maximum possible number you can obtain applying this operation no more than once?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1154"Let's consider one interesting word game. In this game you should transform one word into another through special operations. Let's say we have word w, let's split this word into two non-empty parts x and y so, that w = xy. A split operation is transforming word w = xy into word u = yx. For example, a split operation can transform word ""wordcut"" into word ""cutword"".You are given two words start and end. Count in how many ways we can transform word start into word end, if we apply exactly k split operations consecutively to word start. Two ways are considered different if the sequences of applied operations differ. Two operation sequences are different if exists such number i (1 ≤ i ≤ k), that in the i-th operation of the first sequence the word splits into parts x and y, in the i-th operation of the second sequence the word splits into parts a and b, and additionally x ≠ a holds.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1155"PolandBall has such a convex polygon with n veritces that no three of its diagonals intersect at the same point. PolandBall decided to improve it and draw some red segments. He chose a number k such that gcd(n, k) = 1. Vertices of the polygon are numbered from 1 to n in a clockwise way. PolandBall repeats the following process n times, starting from the vertex 1: Assume you've ended last operation in vertex x (consider x = 1 if it is the first operation). Draw a new segment from vertex x to k-th next vertex in clockwise direction. This is a vertex x + k or x + k - n depending on which of these is a valid index of polygon's vertex.Your task is to calculate number of polygon's sections after each drawing. A section is a clear area inside the polygon bounded with drawn diagonals or the polygon's sides.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1156"As we all know Barney's job is ""PLEASE"" and he has not much to do at work. That's why he started playing ""cups and key"". In this game there are three identical cups arranged in a line from left to right. Initially key to Barney's heart is under the middle cup.  Then at one turn Barney swaps the cup in the middle with any of other two cups randomly (he choses each with equal probability), so the chosen cup becomes the middle one. Game lasts n turns and Barney independently choses a cup to swap with the middle one within each turn, and the key always remains in the cup it was at the start.After n-th turn Barney asks a girl to guess which cup contains the key. The girl points to the middle one but Barney was distracted while making turns and doesn't know if the key is under the middle cup. That's why he asked you to tell him the probability that girl guessed right.Number n of game turns can be extremely large, that's why Barney did not give it to you. Instead he gave you an array a1, a2, ..., ak such that   in other words, n is multiplication of all elements of the given array.Because of precision difficulties, Barney asked you to tell him the answer as an irreducible fraction. In other words you need to find it as a fraction p / q such that , where  is the greatest common divisor. Since p and q can be extremely large, you only need to find the remainders of dividing each of them by 109 + 7.Please note that we want  of p and q to be 1, not  of their remainders after dividing by 109 + 7.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1157"Rick and Morty are playing their own version of Berzerk (which has nothing in common with the famous Berzerk game). This game needs a huge space, so they play it with a computer.In this game there are n objects numbered from 1 to n arranged in a circle (in clockwise order). Object number 1 is a black hole and the others are planets. There's a monster in one of the planet. Rick and Morty don't know on which one yet, only that he's not initially in the black hole, but Unity will inform them before the game starts. But for now, they want to be prepared for every possible scenario.  Each one of them has a set of numbers between 1 and n - 1 (inclusive). Rick's set is s1 with k1 elements and Morty's is s2 with k2 elements. One of them goes first and the player changes alternatively. In each player's turn, he should choose an arbitrary number like x from his set and the monster will move to his x-th next object from its current position (clockwise). If after his move the monster gets to the black hole he wins.Your task is that for each of monster's initial positions and who plays first determine if the starter wins, loses, or the game will stuck in an infinite loop. In case when player can lose or make game infinity, it more profitable to choose infinity game.",['games'],"[1, 0, 0, 0, 0, 0, 0, 0]"1158"Andrew has $$$n$$$ piles with stones. The $$$i$$$-th pile contains $$$a_i$$$ stones. He wants to make his table clean so he decided to put every stone either to the $$$1$$$-st or the $$$n$$$-th pile.Andrew can perform the following operation any number of times: choose $$$3$$$ indices $$$1 \le i < j < k \le n$$$, such that the $$$j$$$-th pile contains at least $$$2$$$ stones, then he takes $$$2$$$ stones from the pile $$$j$$$ and puts one stone into pile $$$i$$$ and one stone into pile $$$k$$$. Tell Andrew what is the minimum number of operations needed to move all the stones to piles $$$1$$$ and $$$n$$$, or determine if it's impossible.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1159"Today, hedgehog Filya went to school for the very first time! Teacher gave him a homework which Filya was unable to complete without your help.Filya is given an array of non-negative integers a1, a2, ..., an. First, he pick an integer x and then he adds x to some elements of the array (no more than once), subtract x from some other elements (also, no more than once) and do no change other elements. He wants all elements of the array to be equal.Now he wonders if it's possible to pick such integer x and change some elements of the array using this x in order to make all elements equal.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1160"There is a road with length $$$l$$$ meters. The start of the road has coordinate $$$0$$$, the end of the road has coordinate $$$l$$$.There are two cars, the first standing at the start of the road and the second standing at the end of the road. They will start driving simultaneously. The first car will drive from the start to the end and the second car will drive from the end to the start.Initially, they will drive with a speed of $$$1$$$ meter per second. There are $$$n$$$ flags at different coordinates $$$a_1, a_2, \ldots, a_n$$$. Each time when any of two cars drives through a flag, the speed of that car increases by $$$1$$$ meter per second.Find how long will it take for cars to meet (to reach the same coordinate). ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1161"Nastya just made a huge mistake and dropped a whole package of rice on the floor. Mom will come soon. If she sees this, then Nastya will be punished.In total, Nastya dropped $$$n$$$ grains. Nastya read that each grain weighs some integer number of grams from $$$a - b$$$ to $$$a + b$$$, inclusive (numbers $$$a$$$ and $$$b$$$ are known), and the whole package of $$$n$$$ grains weighs from $$$c - d$$$ to $$$c + d$$$ grams, inclusive (numbers $$$c$$$ and $$$d$$$ are known). The weight of the package is the sum of the weights of all $$$n$$$ grains in it.Help Nastya understand if this information can be correct. In other words, check whether each grain can have such a mass that the $$$i$$$-th grain weighs some integer number $$$x_i$$$ $$$(a - b \leq x_i \leq a + b)$$$, and in total they weigh from $$$c - d$$$ to $$$c + d$$$, inclusive ($$$c - d \leq \sum\limits_{i=1}^{n}{x_i} \leq c + d$$$).",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1162"Burenka came to kindergarden. This kindergarten is quite strange, so each kid there receives two fractions ($$$\frac{a}{b}$$$ and $$$\frac{c}{d}$$$) with integer numerators and denominators. Then children are commanded to play with their fractions.Burenka is a clever kid, so she noticed that when she claps once, she can multiply numerator or denominator of one of her two fractions by any integer of her choice (but she can't multiply denominators by $$$0$$$). Now she wants know the minimal number of claps to make her fractions equal (by value). Please help her and find the required number of claps!","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1163"Berland has a long and glorious history. To increase awareness about it among younger citizens, King of Berland decided to compose an anthem.Though there are lots and lots of victories in history of Berland, there is the one that stand out the most. King wants to mention it in the anthem as many times as possible.He has already composed major part of the anthem and now just needs to fill in some letters. King asked you to help him with this work.The anthem is the string s of no more than 105 small Latin letters and question marks. The most glorious victory is the string t of no more than 105 small Latin letters. You should replace all the question marks with small Latin letters in such a way that the number of occurrences of string t in string s is maximal.Note that the occurrences of string t in s can overlap. Check the third example for clarification.",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1164"A has a string consisting of some number of lowercase English letters 'a'. He gives it to his friend B who appends some number of letters 'b' to the end of this string. Since both A and B like the characters 'a' and 'b', they have made sure that at this point, at least one 'a' and one 'b' exist in the string.B now gives this string to C and he appends some number of letters 'c' to the end of the string. However, since C is a good friend of A and B, the number of letters 'c' he appends is equal to the number of 'a' or to the number of 'b' in the string. It is also possible that the number of letters 'c' equals both to the number of letters 'a' and to the number of letters 'b' at the same time.You have a string in your hands, and you want to check if it is possible to obtain the string in this way or not. If it is possible to obtain the string, print ""YES"", otherwise print ""NO"" (without the quotes).",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1165"Boboniu gives you  $$$r$$$ red balls,  $$$g$$$ green balls,  $$$b$$$ blue balls,  $$$w$$$ white balls. He allows you to do the following operation as many times as you want:   Pick a red ball, a green ball, and a blue ball and then change their color to white. You should answer if it's possible to arrange all the balls into a palindrome after several (possibly zero) number of described operations. ",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1166"Inflation has occurred in Berlandia, so the store needs to change the price of goods.The current price of good $$$n$$$ is given. It is allowed to increase the price of the good by $$$k$$$ times, with $$$1 \le k \le m$$$, k is an integer. Output the roundest possible new price of the good. That is, the one that has the maximum number of zeros at the end.For example, the number 481000 is more round than the number 1000010 (three zeros at the end of 481000 and only one at the end of 1000010).If there are several possible variants, output the one in which the new price is maximal.If it is impossible to get a rounder price, output $$$n \cdot m$$$ (that is, the maximum possible price).",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"1167"You are given a tuple generator $$$f^{(k)} = (f_1^{(k)}, f_2^{(k)}, \dots, f_n^{(k)})$$$, where $$$f_i^{(k)} = (a_i \cdot f_i^{(k - 1)} + b_i) \bmod p_i$$$ and $$$f^{(0)} = (x_1, x_2, \dots, x_n)$$$. Here $$$x \bmod y$$$ denotes the remainder of $$$x$$$ when divided by $$$y$$$. All $$$p_i$$$ are primes.One can see that with fixed sequences $$$x_i$$$, $$$y_i$$$, $$$a_i$$$ the tuples $$$f^{(k)}$$$ starting from some index will repeat tuples with smaller indices. Calculate the maximum number of different tuples (from all $$$f^{(k)}$$$ for $$$k \ge 0$$$) that can be produced by this generator, if $$$x_i$$$, $$$a_i$$$, $$$b_i$$$ are integers in the range $$$[0, p_i - 1]$$$ and can be chosen arbitrary. The answer can be large, so print the remainder it gives when divided by $$$10^9 + 7$$$",['number theory'],"[0, 0, 0, 0, 1, 0, 0, 0]"1168"Peter had a cube with non-zero length of a side. He put the cube into three-dimensional space in such a way that its vertices lay at integer points (it is possible that the cube's sides are not parallel to the coordinate axes). Then he took a piece of paper and wrote down eight lines, each containing three integers — coordinates of cube's vertex (a single line contains coordinates of a single vertex, each vertex is written exactly once), put the paper on the table and left. While Peter was away, his little brother Nick decided to play with the numbers on the paper. In one operation Nick could swap some numbers inside a single line (Nick didn't swap numbers from distinct lines). Nick could have performed any number of such operations.When Peter returned and found out about Nick's mischief, he started recollecting the original coordinates. Help Peter restore the original position of the points or else state that this is impossible and the numbers were initially recorded incorrectly.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"1169"Little Petya has a birthday soon. Due this wonderful event, Petya's friends decided to give him sweets. The total number of Petya's friends equals to n.Let us remind you the definition of the greatest common divisor: GCD(a1, ..., ak) = d, where d represents such a maximal positive number that each ai (1 ≤ i ≤ k) is evenly divisible by d. At that, we assume that all ai's are greater than zero.Knowing that Petya is keen on programming, his friends has agreed beforehand that the 1-st friend gives a1 sweets, the 2-nd one gives a2 sweets, ..., the n-th one gives an sweets. At the same time, for any i and j (1 ≤ i, j ≤ n) they want the GCD(ai, aj) not to be equal to 1. However, they also want the following condition to be satisfied: GCD(a1, a2, ..., an) = 1. One more: all the ai should be distinct.Help the friends to choose the suitable numbers a1, ..., an.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1170"Let's say you are standing on the $$$XY$$$-plane at point $$$(0, 0)$$$ and you want to reach point $$$(n, n)$$$.You can move only in two directions:   to the right, i. e. horizontally and in the direction that increase your $$$x$$$ coordinate,  or up, i. e. vertically and in the direction that increase your $$$y$$$ coordinate. In other words, your path will have the following structure:   initially, you choose to go to the right or up;  then you go some positive integer distance in the chosen direction (distances can be chosen independently);  after that you change your direction (from right to up, or from up to right) and repeat the process. You don't like to change your direction too much, so you will make no more than $$$n - 1$$$ direction changes.As a result, your path will be a polygonal chain from $$$(0, 0)$$$ to $$$(n, n)$$$, consisting of at most $$$n$$$ line segments where each segment has positive integer length and vertical and horizontal segments alternate.Not all paths are equal. You have $$$n$$$ integers $$$c_1, c_2, \dots, c_n$$$ where $$$c_i$$$ is the cost of the $$$i$$$-th segment.Using these costs we can define the cost of the path as the sum of lengths of the segments of this path multiplied by their cost, i. e. if the path consists of $$$k$$$ segments ($$$k \le n$$$), then the cost of the path is equal to $$$\sum\limits_{i=1}^{k}{c_i \cdot length_i}$$$ (segments are numbered from $$$1$$$ to $$$k$$$ in the order they are in the path).Find the path of the minimum cost and print its cost.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1171"This is an interactive problem.Yui is a girl who enjoys playing Mahjong. She has a mysterious set which consists of tiles (this set can be empty). Each tile has an integer value between $$$1$$$ and $$$n$$$, and at most $$$n$$$ tiles in the set have the same value. So the set can contain at most $$$n^2$$$ tiles.You want to figure out which values are on the tiles. But Yui is shy, she prefers to play a guessing game with you.Let's call a set consisting of three tiles triplet if their values are the same. For example, $$$\{2,\,2,\,2\}$$$ is a triplet, but $$$\{2,\,3,\,3\}$$$ is not.Let's call a set consisting of three tiles straight if their values are consecutive integers. For example, $$$\{2,\,3,\,4\}$$$ is a straight, but $$$\{1,\,3,\,5\}$$$ is not.At first, Yui gives you the number of triplet subsets and straight subsets of the initial set respectively. After that, you can insert a tile with an integer value between $$$1$$$ and $$$n$$$ into the set at most $$$n$$$ times. Every time you insert a tile, you will get the number of triplet subsets and straight subsets of the current set as well.Note that two tiles with the same value are treated different. In other words, in the set $$$\{1,\,1,\,2,\,2,\,3\}$$$ you can find $$$4$$$ subsets $$$\{1,\,2,\,3\}$$$.Try to guess the number of tiles in the initial set with value $$$i$$$ for all integers $$$i$$$ from $$$1$$$ to $$$n$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1172"One day Anna got the following task at school: to arrange several numbers in a circle so that any two neighboring numbers differs exactly by 1. Anna was given several numbers and arranged them in a circle to fulfill the task. Then she wanted to check if she had arranged the numbers correctly, but at this point her younger sister Maria came and shuffled all numbers. Anna got sick with anger but what's done is done and the results of her work had been destroyed. But please tell Anna: could she have hypothetically completed the task using all those given numbers?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1173"The Berland capital is shaken with three bold crimes committed by the Pihsters, a notorious criminal gang.The Berland capital's map is represented by an n × m rectangular table. Each cell of the table on the map represents some districts of the capital. The capital's main detective Polycarpus took a map and marked there the districts where the first three robberies had been committed as asterisks. Deduction tells Polycarpus that the fourth robbery will be committed in such district, that all four robbed districts will form the vertices of some rectangle, parallel to the sides of the map. Polycarpus is good at deduction but he's hopeless at math. So he asked you to find the district where the fourth robbery will be committed.",['geometry'],"[0, 1, 0, 0, 0, 0, 0, 0]"1174"Lately, a national version of a bingo game has become very popular in Berland. There are n players playing the game, each player has a card with numbers. The numbers on each card are distinct, but distinct cards can have equal numbers. The card of the i-th player contains mi numbers.During the game the host takes numbered balls one by one from a bag. He reads the number aloud in a high and clear voice and then puts the ball away. All participants cross out the number if it occurs on their cards. The person who crosses out all numbers from his card first, wins. If multiple people cross out all numbers from their cards at the same time, there are no winners in the game. At the beginning of the game the bag contains 100 balls numbered 1 through 100, the numbers of all balls are distinct.You are given the cards for each player. Write a program that determines whether a player can win the game at the most favorable for him scenario or not.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1175"ZS the Coder and Chris the Baboon arrived at the entrance of Udayland. There is a n × n magic grid on the entrance which is filled with integers. Chris noticed that exactly one of the cells in the grid is empty, and to enter Udayland, they need to fill a positive integer into the empty cell.Chris tried filling in random numbers but it didn't work. ZS the Coder realizes that they need to fill in a positive integer such that the numbers in the grid form a magic square. This means that he has to fill in a positive integer so that the sum of the numbers in each row of the grid (), each column of the grid (), and the two long diagonals of the grid (the main diagonal —  and the secondary diagonal — ) are equal. Chris doesn't know what number to fill in. Can you help Chris find the correct positive integer to fill in or determine that it is impossible?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1176"Piegirl found the red button. You have one last chance to change the inevitable end.The circuit under the button consists of n nodes, numbered from 0 to n - 1. In order to deactivate the button, the n nodes must be disarmed in a particular order. Node 0 must be disarmed first. After disarming node i, the next node to be disarmed must be either node (2·i) modulo n or node (2·i) + 1 modulo n. The last node to be disarmed must be node 0. Node 0 must be disarmed twice, but all other nodes must be disarmed exactly once. Your task is to find any such order and print it. If there is no such order, print -1.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"1177"For an array $$$b$$$ of length $$$m$$$ we define the function $$$f$$$ as  $$$ f(b) = \begin{cases} b[1] & \quad \text{if } m = 1 \\ f(b[1] \oplus b[2],b[2] \oplus b[3],\dots,b[m-1] \oplus b[m]) & \quad \text{otherwise,} \end{cases} $$$ where $$$\oplus$$$ is bitwise exclusive OR.For example, $$$f(1,2,4,8)=f(1\oplus2,2\oplus4,4\oplus8)=f(3,6,12)=f(3\oplus6,6\oplus12)=f(5,10)=f(5\oplus10)=f(15)=15$$$You are given an array $$$a$$$ and a few queries. Each query is represented as two integers $$$l$$$ and $$$r$$$. The answer is the maximum value of $$$f$$$ on all continuous subsegments of the array $$$a_l, a_{l+1}, \ldots, a_r$$$.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1178"Warawreh created a great company called Nanosoft. The only thing that Warawreh still has to do is to place a large picture containing its logo on top of the company's building.The logo of Nanosoft can be described as four squares of the same size merged together into one large square. The top left square is colored with red, the top right square is colored with green, the bottom left square is colored with yellow and the bottom right square is colored with blue.An Example of some correct logos:An Example of some incorrect logos:Warawreh went to Adhami's store in order to buy the needed picture. Although Adhami's store is very large he has only one picture that can be described as a grid of $$$n$$$ rows and $$$m$$$ columns. The color of every cell in the picture will be green (the symbol 'G'), red (the symbol 'R'), yellow (the symbol 'Y') or blue (the symbol 'B').Adhami gave Warawreh $$$q$$$ options, in every option he gave him a sub-rectangle from that picture and told him that he can cut that sub-rectangle for him. To choose the best option, Warawreh needs to know for every option the maximum area of sub-square inside the given sub-rectangle that can be a Nanosoft logo. If there are no such sub-squares, the answer is $$$0$$$.Warawreh couldn't find the best option himself so he asked you for help, can you help him?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1179"Petya got interested in grammar on his third year in school. He invented his own language called Petya's. Petya wanted to create a maximally simple language that would be enough to chat with friends, that's why all the language's grammar can be described with the following set of rules: There are three parts of speech: the adjective, the noun, the verb. Each word in his language is an adjective, noun or verb.  There are two genders: masculine and feminine. Each word in his language has gender either masculine or feminine.  Masculine adjectives end with -lios, and feminine adjectives end with -liala.  Masculine nouns end with -etr, and feminime nouns end with -etra.  Masculine verbs end with -initis, and feminime verbs end with -inites.  Thus, each word in the Petya's language has one of the six endings, given above. There are no other endings in Petya's language.  It is accepted that the whole word consists of an ending. That is, words ""lios"", ""liala"", ""etr"" and so on belong to the Petya's language.  There aren't any punctuation marks, grammatical tenses, singular/plural forms or other language complications.  A sentence is either exactly one valid language word or exactly one statement. Statement is any sequence of the Petya's language, that satisfy both conditions: Words in statement follow in the following order (from the left to the right): zero or more adjectives followed by exactly one noun followed by zero or more verbs.  All words in the statement should have the same gender.After Petya's friend Vasya wrote instant messenger (an instant messaging program) that supported the Petya's language, Petya wanted to add spelling and grammar checking to the program. As Vasya was in the country and Petya didn't feel like waiting, he asked you to help him with this problem. Your task is to define by a given sequence of words, whether it is true that the given text represents exactly one sentence in Petya's language.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1180"Today, like every year at SWERC, the $$$n^2$$$ contestants have gathered outside the venue to take a drone photo. Jennifer, the social media manager for the event, has arranged them into an $$$n\times n$$$ square. Being very good at her job, she knows that the contestant standing on the intersection of the $$$i$$$-th row with the $$$j$$$-th column is $$$a_{i,j}$$$ years old. Coincidentally, she notices that no two contestants have the same age, and that everyone is between $$$1$$$ and $$$n^2$$$ years old.Jennifer is planning to have some contestants hold a banner with the ICPC logo parallel to the ground, so that it is clearly visible in the aerial picture. Here are the steps that she is going to follow in order to take the perfect SWERC drone photo.  First of all, Jennifer is going to select four contestants standing on the vertices of an axis-aligned rectangle.  Then, she will have the two younger contestants hold one of the poles, while the two older contestants will hold the other pole.  Finally, she will unfold the banner, using the poles to support its two ends. Obviously, this can only be done if the two poles are parallel and do not cross, as shown in the pictures below.    Being very indecisive, Jennifer would like to try out all possible arrangements for the banner, but she is worried that this may cause the contestants to be late for the competition. How many different ways are there to choose the four contestants holding the poles in order to take a perfect photo? Two choices are considered different if at least one contestant is included in one but not the other.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1181"Your friend Salem is Warawreh's brother and only loves math and geometry problems. He has solved plenty of such problems, but according to Warawreh, in order to graduate from university he has to solve more graph problems. Since Salem is not good with graphs he asked your help with the following problem.  You are given a complete directed graph with $$$n$$$ vertices without self-loops. In other words, you have $$$n$$$ vertices and each pair of vertices $$$u$$$ and $$$v$$$ ($$$u \neq v$$$) has both directed edges $$$(u, v)$$$ and $$$(v, u)$$$.Every directed edge of the graph is labeled with a single character: either 'a' or 'b' (edges $$$(u, v)$$$ and $$$(v, u)$$$ may have different labels).You are also given an integer $$$m > 0$$$. You should find a path of length $$$m$$$ such that the string obtained by writing out edges' labels when going along the path is a palindrome. The length of the path is the number of edges in it.You can visit the same vertex and the same directed edge any number of times.",['graphs'],"[0, 0, 1, 0, 0, 0, 0, 0]"1182"Parmida is a clever girl and she wants to participate in Olympiads this year. Of course she wants her partner to be clever too (although he's not)! Parmida has prepared the following test problem for Pashmak.There is a sequence a that consists of n integers a1, a2, ..., an. Let's denote f(l, r, x) the number of indices k such that: l ≤ k ≤ r and ak = x. His task is to calculate the number of pairs of indicies i, j (1 ≤ i < j ≤ n) such that f(1, i, ai) > f(j, n, aj).Help Pashmak with the test.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1183"Recently you've discovered a new shooter. They say it has realistic game mechanics.Your character has a gun with magazine size equal to $$$k$$$ and should exterminate $$$n$$$ waves of monsters. The $$$i$$$-th wave consists of $$$a_i$$$ monsters and happens from the $$$l_i$$$-th moment of time up to the $$$r_i$$$-th moments of time. All $$$a_i$$$ monsters spawn at moment $$$l_i$$$ and you have to exterminate all of them before the moment $$$r_i$$$ ends (you can kill monsters right at moment $$$r_i$$$). For every two consecutive waves, the second wave starts not earlier than the first wave ends (though the second wave can start at the same moment when the first wave ends) — formally, the condition $$$r_i \le l_{i + 1}$$$ holds. Take a look at the notes for the examples to understand the process better.You are confident in yours and your character's skills so you can assume that aiming and shooting are instant and you need exactly one bullet to kill one monster. But reloading takes exactly $$$1$$$ unit of time.One of the realistic mechanics is a mechanic of reloading: when you reload you throw away the old magazine with all remaining bullets in it. That's why constant reloads may cost you excessive amounts of spent bullets.You've taken a liking to this mechanic so now you are wondering: what is the minimum possible number of bullets you need to spend (both used and thrown) to exterminate all waves.Note that you don't throw the remaining bullets away after eradicating all monsters, and you start with a full magazine.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1184"Long ago, when Petya was a schoolboy, he was very much interested in the Petr# language grammar. During one lesson Petya got interested in the following question: how many different continuous substrings starting with the sbegin and ending with the send (it is possible sbegin = send), the given string t has. Substrings are different if and only if their contents aren't equal, their positions of occurence don't matter. Petya wasn't quite good at math, that's why he couldn't count this number. Help him!",['strings'],"[0, 0, 0, 0, 0, 0, 1, 0]"1185"Vasya got really tired of these credits (from problem F) and now wants to earn the money himself! He decided to make a contest to gain a profit.Vasya has $$$n$$$ problems to choose from. They are numbered from $$$1$$$ to $$$n$$$. The difficulty of the $$$i$$$-th problem is $$$d_i$$$. Moreover, the problems are given in the increasing order by their difficulties. The difficulties of all tasks are pairwise distinct. In order to add the $$$i$$$-th problem to the contest you need to pay $$$c_i$$$ burles to its author. For each problem in the contest Vasya gets $$$a$$$ burles.In order to create a contest he needs to choose a consecutive subsegment of tasks.So the total earnings for the contest are calculated as follows:   if Vasya takes problem $$$i$$$ to the contest, he needs to pay $$$c_i$$$ to its author;  for each problem in the contest Vasya gets $$$a$$$ burles;  let $$$gap(l, r) = \max\limits_{l \le i < r} (d_{i + 1} - d_i)^2$$$. If Vasya takes all the tasks with indices from $$$l$$$ to $$$r$$$ to the contest, he also needs to pay $$$gap(l, r)$$$. If $$$l = r$$$ then $$$gap(l, r) = 0$$$. Calculate the maximum profit that Vasya can earn by taking a consecutive segment of tasks.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1186"Wabbit is trying to move a box containing food for the rest of the zoo in the coordinate plane from the point $$$(x_1,y_1)$$$ to the point $$$(x_2,y_2)$$$.He has a rope, which he can use to pull the box. He can only pull the box if he stands exactly $$$1$$$ unit away from the box in the direction of one of two coordinate axes. He will pull the box to where he is standing before moving out of the way in the same direction by $$$1$$$ unit.   For example, if the box is at the point $$$(1,2)$$$ and Wabbit is standing at the point $$$(2,2)$$$, he can pull the box right by $$$1$$$ unit, with the box ending up at the point $$$(2,2)$$$ and Wabbit ending at the point $$$(3,2)$$$.Also, Wabbit can move $$$1$$$ unit to the right, left, up, or down without pulling the box. In this case, it is not necessary for him to be in exactly $$$1$$$ unit away from the box. If he wants to pull the box again, he must return to a point next to the box. Also, Wabbit can't move to the point where the box is located.Wabbit can start at any point. It takes $$$1$$$ second to travel $$$1$$$ unit right, left, up, or down, regardless of whether he pulls the box while moving.Determine the minimum amount of time he needs to move the box from $$$(x_1,y_1)$$$ to $$$(x_2,y_2)$$$. Note that the point where Wabbit ends up at does not matter.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1187"Olya has an array of integers $$$a_1, a_2, \ldots, a_n$$$. She wants to split it into tandem repeats. Since it's rarely possible, before that she wants to perform the following operation several (possibly, zero) number of times: insert a pair of equal numbers into an arbitrary position. Help her!More formally:  A tandem repeat is a sequence $$$x$$$ of even length $$$2k$$$ such that for each $$$1 \le i \le k$$$ the condition $$$x_i = x_{i + k}$$$ is satisfied.  An array $$$a$$$ could be split into tandem repeats if you can split it into several parts, each being a subsegment of the array, such that each part is a tandem repeat.  In one operation you can choose an arbitrary letter $$$c$$$ and insert $$$[c, c]$$$ to any position in the array (at the beginning, between any two integers, or at the end).  You are to perform several operations and split the array into tandem repeats or determine that it is impossible. Please note that you do not have to minimize the number of operations. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1188"Dima is a beginner programmer. During his working process, he regularly has to repeat the following operation again and again: to remove every second element from the array. One day he has been bored with easy solutions of this problem, and he has come up with the following extravagant algorithm.Let's consider that initially array contains n numbers from 1 to n and the number i is located in the cell with the index 2i - 1 (Indices are numbered starting from one) and other cells of the array are empty. Each step Dima selects a non-empty array cell with the maximum index and moves the number written in it to the nearest empty cell to the left of the selected one. The process continues until all n numbers will appear in the first n cells of the array. For example if n = 4, the array is changing as follows:  You have to write a program that allows you to determine what number will be in the cell with index x (1 ≤ x ≤ n) after Dima's algorithm finishes.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1189"You are given an array $$$a$$$ of $$$n$$$ elements. Your can perform the following operation no more than $$$n$$$ times: Select three indices $$$x,y,z$$$ $$$(1 \leq x < y < z \leq n)$$$ and replace $$$a_x$$$ with $$$a_y - a_z$$$. After the operation, $$$|a_x|$$$ need to be less than $$$10^{18}$$$.Your goal is to make the resulting array non-decreasing. If there are multiple solutions, you can output any. If it is impossible to achieve, you should report it as well.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1190"Ayush, Ashish and Vivek are busy preparing a new problem for the next Codeforces round and need help checking if their test cases are valid.Each test case consists of an integer $$$n$$$ and two arrays $$$a$$$ and $$$b$$$, of size $$$n$$$. If after some (possibly zero) operations described below, array $$$a$$$ can be transformed into array $$$b$$$, the input is said to be valid. Otherwise, it is invalid.An operation on array $$$a$$$ is:   select an integer $$$k$$$ $$$(1 \le k \le \lfloor\frac{n}{2}\rfloor)$$$  swap the prefix of length $$$k$$$ with the suffix of length $$$k$$$ For example, if array $$$a$$$ initially is $$$\{1, 2, 3, 4, 5, 6\}$$$, after performing an operation with $$$k = 2$$$, it is transformed into $$$\{5, 6, 3, 4, 1, 2\}$$$.Given the set of test cases, help them determine if each one is valid or invalid.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1191"You are given two integers $$$n$$$ and $$$m$$$ and an array $$$a$$$ of $$$n$$$ integers. For each $$$1 \le i \le n$$$ it holds that $$$1 \le a_i \le m$$$.Your task is to count the number of different arrays $$$b$$$ of length $$$n$$$ such that:   $$$1 \le b_i \le m$$$ for each $$$1 \le i \le n$$$, and  $$$\gcd(b_1,b_2,b_3,...,b_i) = a_i$$$ for each $$$1 \le i \le n$$$. Here $$$\gcd(a_1,a_2,\dots,a_i)$$$ denotes the greatest common divisor (GCD) of integers $$$a_1,a_2,\ldots,a_i$$$.Since this number can be too large, print it modulo $$$998\,244\,353$$$.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1192"After the piece of a devilish mirror hit the Kay's eye, he is no longer interested in the beauty of the roses. Now he likes to watch snowflakes.Once upon a time, he found a huge snowflake that has a form of the tree (connected acyclic graph) consisting of n nodes. The root of tree has index 1. Kay is very interested in the structure of this tree.After doing some research he formed q queries he is interested in. The i-th query asks to find a centroid of the subtree of the node vi. Your goal is to answer all queries.Subtree of a node is a part of tree consisting of this node and all it's descendants (direct or not). In other words, subtree of node v is formed by nodes u, such that node v is present on the path from u to root.Centroid of a tree (or a subtree) is a node, such that if we erase it from the tree, the maximum size of the connected component will be at least two times smaller than the size of the initial tree (or a subtree).",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"1193"A team of furry rescue rangers was sitting idle in their hollow tree when suddenly they received a signal of distress. In a few moments they were ready, and the dirigible of the rescue chipmunks hit the road.We assume that the action takes place on a Cartesian plane. The headquarters of the rescuers is located at point (x1, y1), and the distress signal came from the point (x2, y2).Due to Gadget's engineering talent, the rescuers' dirigible can instantly change its current velocity and direction of movement at any moment and as many times as needed. The only limitation is: the speed of the aircraft relative to the air can not exceed  meters per second.Of course, Gadget is a true rescuer and wants to reach the destination as soon as possible. The matter is complicated by the fact that the wind is blowing in the air and it affects the movement of the dirigible. According to the weather forecast, the wind will be defined by the vector (vx, vy) for the nearest t seconds, and then will change to (wx, wy). These vectors give both the direction and velocity of the wind. Formally, if a dirigible is located at the point (x, y), while its own velocity relative to the air is equal to zero and the wind (ux, uy) is blowing, then after  seconds the new position of the dirigible will be .Gadget is busy piloting the aircraft, so she asked Chip to calculate how long will it take them to reach the destination if they fly optimally. He coped with the task easily, but Dale is convinced that Chip has given the random value, aiming only not to lose the face in front of Gadget. Dale has asked you to find the right answer.It is guaranteed that the speed of the wind at any moment of time is strictly less than the maximum possible speed of the airship relative to the air.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"1194"DLS and JLS are bored with a Math lesson. In order to entertain themselves, DLS took a sheet of paper and drew $$$n$$$ distinct lines, given by equations $$$y = x + p_i$$$ for some distinct $$$p_1, p_2, \ldots, p_n$$$.Then JLS drew on the same paper sheet $$$m$$$ distinct lines given by equations $$$y = -x + q_i$$$ for some distinct $$$q_1, q_2, \ldots, q_m$$$.DLS and JLS are interested in counting how many line pairs have integer intersection points, i.e. points with both coordinates that are integers. Unfortunately, the lesson will end up soon, so DLS and JLS are asking for your help.","['geometry', 'math']","[0, 1, 0, 1, 0, 0, 0, 0]"1195"In one school with Vasya there is a student Kostya. Kostya does not like physics, he likes different online games. Every day, having come home, Kostya throws his bag in the farthest corner and sits down at his beloved computer. Kostya even eats glued to the game. A few days ago Kostya bought a new RPG game ""HaresButtle"", which differs from all other games in this genre. It has a huge number of artifacts. As we know, artifacts are divided into basic and composite ones. Only the basic artifacts are available on sale. More powerful composite artifacts are collected from some number of basic artifacts.After the composing composite artifact, all the components disappear.Kostya is the head of the alliance, so he has to remember, what artifacts has not only himself, but also his allies. You must identify by sequence of artifacts purchased by Kostya and his allies, how many and which artifacts has been collected by each of them. It is believed that initially no one has any artifacts. ",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1196"$$$2^k$$$ teams participate in a playoff tournament. The tournament consists of $$$2^k - 1$$$ games. They are held as follows: first of all, the teams are split into pairs: team $$$1$$$ plays against team $$$2$$$, team $$$3$$$ plays against team $$$4$$$ (exactly in this order), and so on (so, $$$2^{k-1}$$$ games are played in that phase). When a team loses a game, it is eliminated, and each game results in elimination of one team (there are no ties). After that, only $$$2^{k-1}$$$ teams remain. If only one team remains, it is declared the champion; otherwise, $$$2^{k-2}$$$ games are played: in the first one of them, the winner of the game ""$$$1$$$ vs $$$2$$$"" plays against the winner of the game ""$$$3$$$ vs $$$4$$$"", then the winner of the game ""$$$5$$$ vs $$$6$$$"" plays against the winner of the game ""$$$7$$$ vs $$$8$$$"", and so on. This process repeats until only one team remains.For example, this picture describes the chronological order of games with $$$k = 3$$$:  Let the string $$$s$$$ consisting of $$$2^k - 1$$$ characters describe the results of the games in chronological order as follows:  if $$$s_i$$$ is 0, then the team with lower index wins the $$$i$$$-th game;  if $$$s_i$$$ is 1, then the team with greater index wins the $$$i$$$-th game;  if $$$s_i$$$ is ?, then the result of the $$$i$$$-th game is unknown (any team could win this game). Let $$$f(s)$$$ be the number of possible winners of the tournament described by the string $$$s$$$. A team $$$i$$$ is a possible winner of the tournament if it is possible to replace every ? with either 1 or 0 in such a way that team $$$i$$$ is the champion.You are given the initial state of the string $$$s$$$. You have to process $$$q$$$ queries of the following form:   $$$p$$$ $$$c$$$ — replace $$$s_p$$$ with character $$$c$$$, and print $$$f(s)$$$ as the result of the query. ",['trees'],"[0, 0, 0, 0, 0, 0, 0, 1]"1197"Quite recently, a very smart student named Jury decided that lectures are boring, so he downloaded a game called ""Black Square"" on his super cool touchscreen phone.In this game, the phone's screen is divided into four vertical strips. Each second, a black square appears on some of the strips. According to the rules of the game, Jury must use this second to touch the corresponding strip to make the square go away. As Jury is both smart and lazy, he counted that he wastes exactly ai calories on touching the i-th strip.You've got a string s, describing the process of the game and numbers a1, a2, a3, a4. Calculate how many calories Jury needs to destroy all the squares?",[],"[0, 0, 0, 0, 0, 0, 0, 0]"1198"For some binary string $$$s$$$ (i.e. each character $$$s_i$$$ is either '0' or '1'), all pairs of consecutive (adjacent) characters were written. In other words, all substrings of length $$$2$$$ were written. For each pair (substring of length $$$2$$$), the number of '1' (ones) in it was calculated.You are given three numbers:  $$$n_0$$$ — the number of such pairs of consecutive characters (substrings) where the number of ones equals $$$0$$$;  $$$n_1$$$ — the number of such pairs of consecutive characters (substrings) where the number of ones equals $$$1$$$;  $$$n_2$$$ — the number of such pairs of consecutive characters (substrings) where the number of ones equals $$$2$$$. For example, for the string $$$s=$$$""1110011110"", the following substrings would be written: ""11"", ""11"", ""10"", ""00"", ""01"", ""11"", ""11"", ""11"", ""10"". Thus, $$$n_0=1$$$, $$$n_1=3$$$, $$$n_2=5$$$.Your task is to restore any suitable binary string $$$s$$$ from the given values $$$n_0, n_1, n_2$$$. It is guaranteed that at least one of the numbers $$$n_0, n_1, n_2$$$ is greater than $$$0$$$. Also, it is guaranteed that a solution exists.",['math'],"[0, 0, 0, 1, 0, 0, 0, 0]"1199"YouKn0wWho has an integer sequence $$$a_1, a_2, \ldots, a_n$$$. He will perform the following operation until the sequence becomes empty: select an index $$$i$$$ such that $$$1 \le i \le |a|$$$ and $$$a_i$$$ is not divisible by $$$(i + 1)$$$, and erase this element from the sequence. Here $$$|a|$$$ is the length of sequence $$$a$$$ at the moment of operation. Note that the sequence $$$a$$$ changes and the next operation is performed on this changed sequence.For example, if $$$a=[3,5,4,5]$$$, then he can select $$$i = 2$$$, because $$$a_2 = 5$$$ is not divisible by $$$i+1 = 3$$$. After this operation the sequence is $$$[3,4,5]$$$.Help YouKn0wWho determine if it is possible to erase the whole sequence using the aforementioned operation.","['math', 'number theory']","[0, 0, 0, 1, 1, 0, 0, 0]"1200"Modern researches has shown that a flock of hungry mice searching for a piece of cheese acts as follows: if there are several pieces of cheese then each mouse chooses the closest one. After that all mice start moving towards the chosen piece of cheese. When a mouse or several mice achieve the destination point and there is still a piece of cheese in it, they eat it and become well-fed. Each mice that reaches this point after that remains hungry. Moving speeds of all mice are equal.If there are several ways to choose closest pieces then mice will choose it in a way that would minimize the number of hungry mice. To check this theory scientists decided to conduct an experiment. They located N mice and M pieces of cheese on a cartesian plane where all mice are located on the line y = Y0 and all pieces of cheese — on another line y = Y1. To check the results of the experiment the scientists need a program which simulates the behavior of a flock of hungry mice.Write a program that computes the minimal number of mice which will remain hungry, i.e. without cheese.",[],"[0, 0, 0, 0, 0, 0, 0, 0]"

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