#include <bits/stdc++.h>
using namespace std;
int a[4];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> a[0] >> a[1] >> a[2] >> a[3];
  if (a[0] < a[2] || a[1] < a[3] || max(a[2], a[3]) - min(a[2], a[3]) > 1)
    cout << -1;
  else {
    if (a[2] == a[3]) {
      if (a[0] == a[2]) {
        if (a[1] == a[2]) {
          cout << -1;
        } else {
          for (int i = 0; i < a[3]; ++i) cout << "74";
          for (int i = a[3]; i < a[1]; ++i) cout << "7";
        }
      } else if (a[0] > a[2]) {
        for (int i = a[2] + 1; i < a[0]; ++i) cout << "4";
        for (int i = 0; i < a[2]; ++i) cout << "47";
        for (int i = a[3]; i < a[1]; ++i) cout << "7";
        cout << "4";
      }
    } else if (a[2] > a[3]) {
      if (a[1] == a[3])
        cout << -1;
      else {
        for (int i = a[2]; i < a[0]; ++i) cout << "4";
        for (int i = 0; i < a[2]; ++i) cout << "47";
        for (int i = a[2]; i < a[1]; ++i) cout << "7";
      }
    } else {
      if (a[0] == a[2])
        cout << -1;
      else {
        cout << "7";
        for (int i = a[2]; i < a[0]; ++i) cout << "4";
        for (int i = 2; i < a[3]; ++i) cout << "74";
        for (int i = a[3] - 1; i < a[1]; ++i) cout << "7";
        cout << "4";
      }
    }
  }
  return 0;
}
