func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int i, j, k, l, max1 = 0, n, p, sum = 0;     string a, b, c;     cin >> n;     int x[26] = {0};     cin >> a;     if (n > 26)       cout <<  -1  << endl;     else {       for (i = 0; i < n; i++) {         p = a[i] -  a ;         x[p]++;       }       for (i = 0; i < 26; i++) {         if (x[i] > 1) {           sum += (x[i] - 1);           if (x[i] > max1) max1 = x[i];         }       }       cout << sum << endl;     }     return 0;   }   