func_code_string: #include <bits/stdc++.h>   using namespace std;   map<long long, int> m;   int main() {     int n;     scanf( %d , &n);     long long count = 0;     int flag = 0;     for (int i = 0; i < n; i++) {       long long c;       cin >> c;       if (c > 0) {         m[c] += 1;         if (m[c] == 2) count++;         if (m[c] > 2) flag = 1;       }     }     if (flag)       cout <<  -1  << endl;     else       cout << count << endl;     return 0;   }   