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