#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;
}
