func_code_string: #include <bits/stdc++.h>   using namespace std;   bool lucky(char a) {     if (a ==  4  || a ==  7 )       return true;     else       return false;   }   int main() {     long long int a, b, c, d;     vector<bool> res;     cin >> a >> b >> c >> d;     if (abs(c - d) > 1 || min(a, b) < max(c, d)) {       puts( -1 );       return 0;     }     if (c > d) {       for (long long int i = 0; i < ((long long int)(a - d)); i++) cout << 4;       for (long long int i = 0; i < ((long long int)(d)); i++) cout << 74;       for (long long int i = 0; i < ((long long int)(b - d)); i++) cout << 7;     } else if (c < d) {       cout << 7;       for (long long int i = 0; i < ((long long int)(a - c)); i++) cout << 4;       for (long long int i = 0; i < ((long long int)(c - 1)); i++) cout << 74;       for (long long int i = 0; i < ((long long int)(b - c)); i++) cout << 7;       cout << 4;     } else {       if (a + b < c + d + 1) {         puts( -1 );         return 0;       }       for (long long int i = 0; i < ((long long int)(a - c)); i++) cout << 4;       if (a - c > 0) {         for (long long int i = 0; i < ((long long int)(c - 1)); i++) cout << 74;         for (long long int i = 0; i < ((long long int)(b - c + 1)); i++)           cout << 7;         cout << 4;       } else {         cout << 7;         for (long long int i = 0; i < ((long long int)(c)); i++) cout << 47;         for (long long int i = 0; i < ((long long int)(b - 1 - c)); i++)           cout << 7;       }     }     puts(  );     return 0;   }   