You are given a string S of length n with each character being one of the first m lowercase English letters.

Calculate how many different strings T of length n composed from the first m lowercase English letters exist such that the length of LCS (longest common subsequence) between S and T is n-1.

Recall that LCS of two strings S and T is the longest string C such that C both in S and T as a subsequence.

The first line contains two numbers n and m denoting the length of string S and number of first English lowercase characters forming the character set for strings (1 \le n \le 100000, 2 \le m \le 26).

The second line contains string S.

Print the only line containing the answer.

For the first sample, the 6 possible strings T are: aab, aac, aba, aca, baa, caa.

For the second sample, the 11 possible strings T are: aaa, aac, aba, abb, abc, aca, acb, baa, bab, caa, cab.

For the third sample, the only possible string T is b.