#include <bits/stdc++.h>
using namespace std;
int replay[3];
bool ok;
int main() {
  int a1, a2, a3, a4;
  cin >> a1 >> a2 >> a3 >> a4;
  if (abs(a4 - a3) > 1) {
    cout << -1;
    exit(0);
  }
  int c1 = 0, c2 = 0;
  string ans = "";
  if (a4 > a3) {
    c2++;
    ans += '7';
  } else if (a3 > a4) {
    c1++;
    ans += '4';
  } else if (a2 > 1 && a1 == 1) {
    c2++;
    ans += '7';
  } else {
    c1++;
    ans += '4';
  }
  int cnt1 = 0, cnt2 = 0;
  for (int i = 1;; i++) {
    if (ans[i - 1] == '4') {
      ans += '7';
      cnt1++;
      c2++;
    } else {
      ans += '4';
      cnt2++;
      c1++;
    }
    if (cnt1 == a3 && cnt2 == a4) break;
  }
  if ((c1 > a1 || c2 > a2) && (c2 > a1 || c1 > a2)) {
    cout << -1;
    return 0;
  }
  if ((c1 > a1 || c2 > a2)) {
    swap(c1, c2);
    swap(cnt1, cnt2);
    for (int i = 0; i < ans.size(); i++) {
      if (ans[i] == '4')
        ans[i] = '7';
      else if (ans[i] == '7')
        ans[i] = '4';
    }
  }
  replay[0] = replay[1] = -1;
  for (int i = 0; i < ans.size(); i++) {
    if (ans[i] == '4' && replay[0] == -1) replay[0] = i;
    if (ans[i] == '7') replay[1] = i;
  }
  for (int i = 0; i < ans.size(); i++) {
    cout << ans[i];
    if (replay[0] == i) {
      while (c1 < a1) {
        cout << '4';
        c1++;
      }
    }
    if (replay[1] == i) {
      while (c2 < a2) {
        cout << '7';
        c2++;
      }
    }
  }
}
