#include <bits/stdc++.h>   const int maxn = 1e5 + 1;   int n, m, l = 1;   long long a;   char s[maxn];   int main() {     scanf( %d%d%s , &n, &m, s + 1);     for (int i = 1; i <= n; i++)       if (s[i] != s[i - 1]) a += n * (m - 1);     for (int i = 2; i <= n; i++)       if (l == 1 && s[i] != s[i - 1] || l > 1 && s[i] == s[i - 2])         ++l;       else if (a -= 1ll * l * (l - 1) >> 1)         l = 1 + (s[i] != s[i - 1]);     printf( %lld n , a -= 1ll * l * (l - 1) >> 1);     return 0;   }   