func_code_string: #include <bits/stdc++.h>   long long a[10000];   using namespace std;   int main() {     long long n, i, j, c;     cin >> n;     for (i = 1; i < n + 1; i++) cin >> a[i];     for (i = 1; i < n + 1; i++) {       for (j = i + 1; j < n + 1; j++) {         if (a[i] > a[j]) {           c = a[i];           a[i] = a[j];           a[j] = c;         }       }     }     i = 1;     while ((a[i] == 0) && (i < n + 1)) i++;     int rez = 0;     j = i;     while ((a[j] != a[j + 2]) && (j < n)) {       if (a[j] == a[j + 1]) rez++;       j++;     }     if (i == n + 1)       cout << rez;     else {       if (j == n)         cout << rez;       else         cout << -1;     }     return 0;   }   