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A9628 | No to Palindromes!

时间限制1s
内存限制256MB
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题目描述

Paul hates palindromes. He assumes that string $s$ is tolerable if each its character is one of the first $p$ letters of the English alphabet and $s$ doesn't contain any palindrome contiguous substring of length 2 or more.

Paul has found a tolerable string $s$ of length $n$ . Help him find the lexicographically next tolerable string of the same length or else state that such string does not exist.

输入格式

The first line contains two space-separated integers: $n$ and $p$ ( $1<=n<=1000$ ; $1<=p<=26$ ). The second line contains string $s$ , consisting of $n$ small English letters. It is guaranteed that the string is tolerable (according to the above definition).

输出格式

If the lexicographically next tolerable string of the same length exists, print it. Otherwise, print "NO" (without the quotes).

输入输出样例

输入 #1
3 3
cba
输出 #1
NO
输入 #2
3 4
cba
输出 #2
cbd
输入 #3
4 4
abcd
输出 #3
abda
C++ 编辑器
输入
输出