func_code_string: #include <bits/stdc++.h>   using namespace std;   int n;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     cin >> n;     char ch;     int Sum = 0, Count = 0;     n /= 2;     for (int i = 1; i <= n; i++) {       cin >> ch;       if (ch ==  4  || ch ==  7 ) {         Count++;       }       Sum += ch -  0 ;     }     for (int i = 1; i <= n; i++) {       cin >> ch;       if (ch ==  4  || ch ==  7 ) {         Count++;       }       Sum -= ch -  0 ;     }     cout << (Sum == 0 && Count == n * 2 ?  YES  :  NO );     return 0;   }   