func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     string s;     static int x[27];     int n, k;     cin >> n >> k;     cin >> s;     for (int i = 0; i < k; i++) {       char r;       cin >> r;       x[r -  a ] = 1;     }     long long res = 0, tr = 0;     for (int i = 0; s[i]; i++) {       if (x[s[i] -  a ])         tr++;       else {         res += (tr * (tr + 1)) / 2;         tr = 0;       }     }     res += (tr * (tr + 1)) / 2;     cout << res;     return 0;   }   