#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c, d;
  while (cin >> a >> b >> c >> d) {
    if (a < c || a < d || b < c || b < d)
      cout << -1 << endl;
    else {
      if (abs(c - d) > 1 || a + b <= c + d)
        cout << -1 << endl;
      else {
        if (d > c) {
          cout << 74;
          for (int i = d; i < a; i++) cout << 4;
          for (int i = 1; i < d - 1; i++) cout << 74;
          cout << 7;
          for (int i = d; i < b; i++) cout << 7;
          cout << 4;
        } else if (c != d) {
          for (int i = c; i < a; i++) cout << 4;
          for (int i = 0; i < c; i++) cout << 47;
          for (int i = c; i < b; i++) cout << 7;
        } else {
          if (a >= c + 1) {
            for (int i = c; i < a - 1; i++) cout << 4;
            for (int i = 0; i < c; i++) cout << 47;
            for (int i = c; i < b; i++) cout << 7;
            cout << 4;
          } else {
            cout << 7;
            for (int i = 0; i < c; i++) cout << 47;
            for (int i = c + 1; i < b; i++) cout << 7;
          }
        }
        cout << endl;
      }
    }
  }
}
