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