#include <bits/stdc++.h>
using namespace std;
int a, b, c, d;
string s;
int main() {
  cin >> a >> b >> c >> d;
  if (min(a, b) < max(c, d) || abs(c - d) > 1 || (c == a && b == d && c == d))
    cout << -1;
  else {
    if (c > d) {
      for (int i = 0; i < a - c; i++) cout << 4;
      for (int i = 0; i < c; i++) cout << 47;
      for (int i = 0; i < b - c; i++) cout << 7;
    } else if (c < d) {
      cout << 7;
      for (int i = 0; i < a - d + 1; i++) cout << 4;
      for (int i = 0; i < d - 2; i++) cout << 74;
      for (int i = 0; i < b - d; i++) cout << 7;
      cout << 74;
    } else {
      if (c == a) {
        cout << 7;
        for (int i = 0; i < c; i++) cout << 47;
        for (int i = 0; i < b - d - 1; i++) cout << 7;
      } else {
        for (int i = 0; i < a - c - 1; i++) cout << 4;
        for (int i = 0; i < c; i++) cout << 47;
        for (int i = 0; i < b - d; i++) cout << 7;
        cout << 4;
      }
    }
  }
  return 0;
}
