#include <bits/stdc++.h>   using namespace std;   int n, A[100], B[100], t, r, x;   string s =   ;   int main() {     cin >> n;     for (int i = 0; i <= n; i++) {       r = 0;       for (int j = 0; j <= n; j++) {         if ((t + r) == n) {           x = 1;           break;         }         r = r + 7;       }       if (x == 1) break;       t = t + 4;     }     if (x == 1) {       for (int i = 0; i < t / 4; i++) s +=  4 ;       for (int i = 0; i < r / 7; i++) s +=  7 ;     } else {       s =  -1 ;     }     cout << s;   }   