#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  if (c > a || c > b || d > a || d > b || abs(c - d) >= 2 ||
      (a == 1 && b == 1)) {
    cout << -1 << endl;
    return 0;
  }
  string ans = "";
  if (c > d) {
    string s = "47";
    for (int i = 0; i < c; i++) ans += s;
    a -= c;
    b -= c;
    if (a < 0 || b < 0) {
      cout << -1 << endl;
      return 0;
    }
    while (a > 0) (a--, cout << 4);
    cout << ans;
    while (b > 0) (b--, cout << 7);
    cout << endl;
    return 0;
  }
  if (d > c) {
    string s = "74";
    for (int i = 0; i < d; i++) ans += s;
    a -= d;
    b -= d;
    if (a < 0 || b < 0) {
      cout << -1 << endl;
      return 0;
    }
    cout << ans[0];
    while (a > 0) (a--, cout << 4);
    for (int i = 1; i < (int)ans.size() - 1; i++) cout << ans[i];
    while (b > 0) (b--, cout << 7);
    cout << 4 << endl;
    return 0;
  }
  if (b > a && 1) {
    if (b < c + 1) {
      cout << -1 << endl;
      return 0;
    }
    string s = "74";
    for (int i = 0; i < c; i++) ans += s;
    ans += "7";
    a -= c;
    b -= c;
    b--;
    if (a < 0 || b < 0) {
      cout << -1 << endl;
      return 0;
    }
    if (a == 0) {
      while (a > 0) (a--, cout << 4);
      cout << ans;
      while (b > 0) (b--, cout << 7);
      cout << endl;
      return 0;
    }
    a += c;
    b++;
    b += c;
  }
  ans = "";
  if (a < c + 1) {
    cout << -1 << endl;
    return 0;
  }
  string s = "47";
  for (int i = 0; i < c; i++) ans += s;
  b -= c;
  a -= c;
  a--;
  if (a < 0 || b < 0) {
    cout << -1 << endl;
    return 0;
  }
  while (a > 0) (a--, cout << 4);
  cout << ans;
  while (b > 0) (b--, cout << 7);
  cout << 4 << endl;
  return 0;
}
