#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5, mod = 1e9 + 7;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int c4, c7, c47, c74;
  cin >> c4 >> c7 >> c47 >> c74;
  if (max(c47, c74) > min(c4, c7) || abs(c74 - c47) > 1) return cout << -1, 0;
  string ans = "";
  int cnt4 = 0, cnt7 = 0;
  if (c47 > c74) {
    for (int i = 0; i < c47; i++) {
      ans += "47";
      cnt4++;
      cnt7++;
    }
    if (cnt4 > c4 || cnt7 > c7) return cout << -1, 0;
    c4 -= cnt4;
    while (c4--) cout << 4;
    cout << ans;
    c7 -= cnt7;
    while (c7--) cout << 7;
  } else if (c47 == c74) {
    cnt4 = 1;
    ans.push_back('4');
    for (int i = 0; i < c47; i++) {
      ans += "74";
      cnt4++;
      cnt7++;
    }
    if (cnt4 > c4 || cnt7 > c7) {
      cnt4 = 0;
      cnt7 = 1;
      ans.clear();
      for (int i = 0; i < c47; i++) {
        ans += "47";
        cnt4++;
        cnt7++;
      }
      if (cnt4 > c4 || cnt7 > c7) return cout << -1, 0;
      cout << 7;
      c4 -= cnt4;
      while (c4--) cout << 4;
      cout << ans;
      c7 -= cnt7;
      while (c7--) cout << 7;
      return 0;
    }
    c4 -= cnt4;
    while (c4--) cout << 4;
    ans.pop_back();
    cout << ans;
    c7 -= cnt7;
    while (c7--) cout << 7;
    cout << 4;
  } else {
    cnt4 = cnt7 = 1;
    for (int i = 1; i < c74; i++) {
      ans += "74";
      cnt4++;
      cnt7++;
    }
    if (cnt4 > c4 || cnt7 > c7) return cout << -1, 0;
    cout << "74";
    c4 -= cnt4;
    while (c4--) cout << 4;
    ans.pop_back();
    cout << ans;
    c7 -= cnt7;
    while (c7--) cout << 7;
    cout << 4;
  }
  return 0;
}
