#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c, d, i;
  string r;
  cin >> a >> b >> c >> d;
  if (abs(d - c) > 1) return cout << -1 << endl, 0;
  if (c > d) {
    a -= c, b -= c;
    while (c--) r += "47";
  } else if (c < d) {
    a -= d, b -= d;
    while (d--) r += "74";
  } else {
    a -= c, b -= c;
    while (c--) r += "47";
    if (a > 0)
      r = r + "4", --a;
    else
      r = "7" + r, --b;
  }
  if (a < 0 || b < 0) return cout << -1 << endl, 0;
  cout << r.front();
  while (a--) cout << '4';
  for (i = 1; i < r.size() - 1; ++i) cout << r[i];
  while (b--) cout << '7';
  cout << r.back() << endl;
  return 0;
}
