#include <bits/stdc++.h>
using namespace std;
void solve() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  if (abs(c - d) > 1) {
    cout << -1 << '\n';
    return;
  }
  if (min(a, b) < max(c, d)) {
    cout << -1 << '\n';
    return;
  }
  int minn = min(c - 1, d);
  a -= minn;
  b -= minn;
  c -= minn;
  d -= minn;
  string ans;
  while (a > 0) ans += '4', a--;
  if (d >= c && ans.size() > 1) ans.pop_back(), a++;
  while (minn > 0) ans += "74", minn--;
  bool ok = b > 1;
  while (b > 0) ans += '7', b--;
  c--;
  if (d - c > 1)
    ans.pop_back(), b++;
  else if (d - c > 0 && a == 0 && ok)
    ans.pop_back(), b++;
  if (d - c > 0 && a > 0) ans += '4', a--, d--;
  if (d - c > 0 && b > 0) ans = '7' + ans, b--, d--;
  if (a != 0 || b != 0 || c != 0 || d != 0) {
    cout << -1 << '\n';
    return;
  }
  cout << ans << '\n';
}
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  solve();
  return 0;
}
