#include <bits/stdc++.h>
using namespace std;
const int maxn = 1000000 + 10;
const int INF = 1e9 + 7;
const int MOD = 1e9 + 7;
const double eps = 1e-10;
const double pi = acos(-1);
int T, cases, n, m;
int main() {
  ios::sync_with_stdio(false);
  ;
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  if (c > a || c > b || d > a || d > b || c + d >= a + b || abs(c - d) > 1) {
    cout << "-1" << endl;
    return 0;
  }
  if (c == d) {
    if (a == c) {
      for (int i = 1; i <= c; i++) cout << "74";
      for (int i = c + 1; i <= b; i++) cout << "7";
      cout << endl;
    } else {
      for (int i = c + 1; i <= a; i++) cout << "4";
      for (int i = 1; i <= c - 1; i++) cout << "74";
      for (int i = d; i <= b; i++) cout << "7";
      cout << "4";
      cout << endl;
    }
  } else if (c == d + 1) {
    for (int i = c; i <= a; i++) cout << "4";
    for (int i = 1; i <= d; i++) cout << "74";
    for (int i = d + 1; i <= b; i++) cout << "7";
    cout << endl;
  } else {
    cout << "7";
    for (int i = c + 1; i <= a; i++) cout << "4";
    for (int i = 1; i <= c - 1; i++) cout << "74";
    for (int i = d; i <= b; i++) cout << "7";
    cout << "4";
    cout << endl;
  }
  return 0;
}
