#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, c, d, x, y, z;
  cin >> a >> b >> c >> d;
  if (a < c || b < c || a < d || b < d || abs(c - d) > 1) {
    cout << "-1\n";
    return 0;
  }
  string ans, temp;
  x = a, y = b;
  if (c > d) {
    for (int i = 0; i < c; i++)
      ans.push_back('4'), ans.push_back('7'), a--, b--;
    if (a < 0 || b < 0) {
      cout << "-1\n";
      return 0;
    }
    while (a) temp.push_back('4'), a--;
    while (b) ans.push_back('7'), b--;
    ans = temp + ans;
  } else if (d > c) {
    for (int i = 0; i < d; i++)
      ans.push_back('7'), ans.push_back('4'), a--, b--;
    if (a < 0 || b < 0) {
      cout << "-1\n";
      return 0;
    }
    if (b) {
      ans[ans.size() - 1] = '7', b--;
      while (b) ans.push_back('7'), b--;
      ans.push_back('4');
    }
    reverse(ans.begin(), ans.end());
    if (a) {
      ans[ans.size() - 1] = '4', a--;
      while (a) ans.push_back('4'), a--;
      ans.push_back('7');
    }
    reverse(ans.begin(), ans.end());
  } else {
    for (int i = 0; i < c; i++)
      ans.push_back('4'), ans.push_back('7'), a--, b--;
    ans.push_back('4'), a--;
    if (a < 0 || b < 0) {
      a = x, b = y;
      ans.clear();
      for (int i = 0; i < d; i++)
        ans.push_back('7'), ans.push_back('4'), a--, b--;
      ans.push_back('7'), b--;
      if (a < 0 || b < 0) {
        cout << "-1\n";
        return 0;
      }
      while (b) ans.push_back('7'), b--;
      reverse(ans.begin(), ans.end());
      if (a) {
        ans[ans.size() - 1] = '4', a--;
        while (a) ans.push_back('4'), a--;
        ans.push_back('7');
      }
      reverse(ans.begin(), ans.end());
    }
    if (b) {
      ans[ans.size() - 1] = '7', b--;
      while (b) ans.push_back('7'), b--;
      ans.push_back('4');
    }
    while (a) temp.push_back('4'), a--;
    ans = temp + ans;
  }
  cout << ans << "\n";
  return 0;
}
