#include <bits/stdc++.h>
using namespace std;
const int M = 2e6 + 5;
int32_t main() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  if (abs(c - d) > 1) return cout << -1 << endl, 0;
  string ans = "";
  if (max(c, d) > min(a, b)) return cout << -1 << endl, 0;
  if (c == d + 1) {
    int t4 = a - c;
    int t7 = b - c;
    while (t4--) ans += "4";
    while (c--) ans += "47";
    while (t7--) ans += "7";
    return cout << ans << endl, 0;
  }
  if (c + 1 == d) {
    int t4 = a - d;
    int t7 = b - d;
    if (d == 1) {
      while (b--) ans += "7";
      while (a--) ans += "4";
      return cout << ans << endl, 0;
    }
    ans += "7";
    while (t4--) ans += "4";
    ans += "4";
    d--;
    int y = d - 1;
    while (y) ans += "74", y--;
    while (t7--) ans += "7";
    ans += "74";
    return cout << ans << endl, 0;
  }
  if (c == d) {
    if (max(a, b) < max(c, d) + 1) return cout << -1 << endl, 0;
    if (a >= c + 1) {
      int t4 = a - c;
      int t7 = b - c;
      while (t4--) ans += "4";
      int u = d - 1;
      while (u--) ans += "74";
      while (t7--) ans += "7";
      ans += "74";
    } else {
      int t7 = b - c;
      while (d--) ans += "74";
      while (t7--) ans += "7";
    }
    return cout << ans << endl, 0;
  }
  return 0;
}
