#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cout.tie(0);
  cin.tie(0);
  int c4, c7, c47, c74;
  cin >> c4 >> c7 >> c47 >> c74;
  if (abs(c47 - c74) > 1) {
    cout << -1;
    return 0;
  } else if (c47 == c74 + 1) {
    if (c4 - c74 <= 0 || c7 - c74 <= 0) {
      cout << -1;
      return 0;
    }
    cout << string(c4 - c74, '4');
    for (int i = 0; i < c74; i++) cout << "74";
    cout << string(c7 - c74, '7');
  } else if (c74 == c47 + 1) {
    if (c7 - c47 <= 0 || c4 - c47 <= 0) {
      cout << -1;
      return 0;
    }
    cout << '7';
    for (int i = 0; i < c47; i++) {
      cout << "4";
      if (i == 0 && c4 - c47 - 1 > 0) cout << string(c4 - c47 - 1, '4');
      cout << "7";
    }
    if (c7 - c47 - 1) cout << string(c7 - c47 - 1, '7');
    cout << 4;
  } else {
    if (c47 + 1 > c4) {
      if (c74 + 1 > c7 || c4 < c74) {
        cout << -1;
        return 0;
      }
      for (int i = 0; i < c74; i++) {
        cout << "74";
        if (c4 - c74 && i == 0) cout << string(c4 - c74, '4');
      }
      cout << string(c7 - c74, '7');
    } else {
      if (c7 < c47) {
        cout << -1;
        return 0;
      }
      if (c4 - c47 - 1) cout << string(c4 - c47 - 1, '4');
      for (int i = 0; i < c47; i++) cout << "47";
      if (c7 - c47) cout << string(c7 - c47, '7');
      cout << "4";
    }
  }
}
