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D. LCS Again

time limit per test

2 secondsmemory limit per test

256 megabytesinput

standard inputoutput

standard outputYou 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.

Input

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 ≤ *n* ≤ 100 000, 2 ≤ *m* ≤ 26).

The second line contains string *S*.

Output

Print the only line containing the answer.

Examples

Input

3 3

aaa

Output

6

Input

3 3

aab

Output

11

Input

1 2

a

Output

1

Input

10 9

abacadefgh

Output

789

Note

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.

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