#include <bits/stdc++.h>
using namespace std;
int fours, sevens, fourseven, sevenfour;
int main() {
  cin >> fours >> sevens >> fourseven >> sevenfour;
  if (abs(fourseven - sevenfour) > 1) return cout << -1, 0;
  string x = "";
  int ifours = 0, isevens = 0;
  if (fourseven == sevenfour) {
    if (fours >= fourseven + 1 && sevens >= fourseven) {
      for (int i = 0; i < fourseven; i++) x += "47";
      ifours = fourseven + 1;
      isevens = fourseven;
      x += "4";
    } else if (fours >= fourseven && sevens >= fourseven + 1) {
      for (int i = 0; i < fourseven; i++) x += "74";
      ifours = fourseven;
      isevens = fourseven + 1;
      x += "7";
    } else
      return cout << -1, 0;
  } else if (fourseven > sevenfour) {
    for (int i = 0; i < fourseven; i++) x += "47";
    isevens = fourseven;
    ifours = fourseven;
  } else {
    for (int i = 0; i < sevenfour; i++) x += "74";
    isevens = sevenfour;
    ifours = sevenfour;
  }
  if (isevens > sevens || ifours > fours) return cout << -1, 0;
  if (sevens > isevens) {
    string a = "";
    int tmp = sevens - isevens;
    while (tmp--) a += '7';
    int lst = -1;
    for (int i = 0; i < x.size(); i++)
      if (x[i] == '7') lst = i;
    if (lst == -1) return cout << -1, 0;
    x = x.substr(0, lst + 1) + a + x.substr(lst + 1);
  }
  if (fours > ifours) {
    string a = "";
    int tmp = fours - ifours;
    while (tmp--) a += '4';
    int lst = 1e6;
    for (int i = x.size() - 1; i >= 0; i--)
      if (x[i] == '4') lst = i;
    if (lst == 1e6) return cout << -1, 0;
    x = x.substr(0, lst + 1) + a + x.substr(lst + 1);
  }
  cout << x;
  return 0;
}
