func_code_string: #include <bits/stdc++.h>   using namespace std;   int a, b, c, d, p;   int main() {     cin >> a >> b >> c >> d;     d -= c - 1;     a -= c;     b -= c;     if (d == 2) {       a--;       b--;       p = 3;     }     if (d == 1) {       if (a) {         a--;         p = 1;       } else {         b--;         p = 2;       }     }     if (a < 0 || b < 0 || d > 2 || d < 0)       cout <<  -1 ;     else {       if (p & 2) cout <<  7 ;       for (; a > 0; a--) cout <<  4 ;       for (; c > 0; c--) cout <<  47 ;       for (; b > 0; b--) cout <<  7 ;       if (p & 1) cout <<  4 ;     }     return 0;   }   