codeforces260div2A,B,C_html/css

B：分別寫出來1，2，3，4，的n次方對5取余。你會發現和對5取余有一個循環節。如果%4 = 0，輸出4，否則輸出0.

寫一個大數取余就過了。

B. Fedya and Maths

time limit per test

memory limit per test

input

output

Fedya studies in a gymnasium. Fedya's maths hometask is to calculate the following expression:

for given value of n. Fedya managed to complete the task. Can you? Note that given number n can be extremely large (e.g. it can exceed any integer type of your programming language).

Input

The single line contains a single integer n (0?≤?n?≤?10105). The number doesn't contain any leading zeroes.

Output

Print the value of the expression without leading zeros.

Sample test(s)

input

output

input

124356983594583453458888889

output

Note

Operation x mod y means taking remainder after division x by y.

Note to the first sample:

#include #include #include #include #include #include #include #include #include #include #include #include 

先根據數字進行哈希，然后線性的dp一遍，dp[i][1] = ma(dp[i-2][0], dp[i-2][1]) + vis[i]*i,dp[i][0] = max(dp[i-1][0], dp[i-1][1]).1代表取這個數，0代表不取。注意數據類型要用long long。

C. Boredom

time limit per test

memory limit per test

input

output

Alex doesn't like boredom. That's why whenever he gets bored, he comes up with games. One long winter evening he came up with a game and decided to play it.

Given a sequence a consisting of n integers. The player can make several steps. In a single step he can choose an element of the sequence (let's denote it ak) and delete it, at that all elements equal to ak?+?1 and ak?-?1 also must be deleted from the sequence. That step brings ak points to the player.

Alex is a perfectionist, so he decided to get as many points as possible. Help him.

Input

The first line contains integer n (1?≤?n?≤?105) that shows how many numbers are in Alex's sequence.

The second line contains n integers a1, a2, ..., an (1?≤?ai?≤?105).

Output

Print a single integer ? the maximum number of points that Alex can earn.

Sample test(s)

input

21 2

output

input

31 2 3

output

input

91 2 1 3 2 2 2 2 3

output

10

Note

Consider the third test example. At first step we need to choose any element equal to 2. After that step our sequence looks like this [2,?2,?2,?2]. Then we do 4 steps, on each step we choose any element equals to 2. In total we earn 10 points.

#include #include #include #include #include #include #include #include #include #include #include #include 

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