func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     int n = 5, sum = 0;     while (n--) {       int a;       cin >> a;       sum += a;     }     if (sum == 0) {       cout << -1 << endl;       return 0;     }     cout << (sum % 5 == 0 ? sum / 5 : -1) << endl;   }   