#include <bits/stdc++.h>   using namespace std;   int readInt() {     int a;     scanf( %d , &a);     return a;   }   long long readLong() {     long long a;     scanf( %lld , &a);     return a;   }   void readString(char *s) { scanf(  %s , s); }   const int N = 100005;   char s[N];   vector<pair<int, int>> comp;   int f[26];   int dp[N];   void solve() {     int n = readInt();     int m = readInt();     readString(s + 1);     int last = 1;     for (int i = (1); i <= (n); ++i) {       if (s[i] != s[i + 1]) {         comp.emplace_back(s[i] -  a , i - last + 1);         last = i + 1;       }       f[s[i] -  a ]++;     }     long long ans = (int)(comp).size() * (n * 1ll * m - n);     dp[1] = 1;     for (int i = (2); i <= (n); ++i) {       if (s[i] != s[i - 1] && s[i] == s[i - 2])         dp[i] = 1 + dp[i - 1];       else if (s[i] != s[i - 1])         dp[i] = 2;       else         dp[i] = 1;       ans -= dp[i] - 1;     }     printf( %lld , ans);   }   int main() {     int t = 1;     while (t--) solve();     return 0;   }   