func_code_string: #include <bits/stdc++.h>   int main() {     int n, y[27] = {}, i, c = 0;     char x[100001];     scanf( %d %s , &n, x);     for (i = 0; i < n; i++)       if (!y[x[i] - 97]) {         y[x[i] - 97]++;         c++;       }     if (n <= 26)       printf( %d , n - c);     else       printf( -1 );   }   