#include <bits/stdc++.h>
using namespace std;
static const double EPS = 1e-6;
const long double pi = acos(-1.0);
int dx[] = {0, 1, 0, -1, 1, 1, -1, -1, 0},
    dy[] = {1, 0, -1, 0, 1, -1, 1, -1, 0};
int main() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  string ans;
  if (c == d) {
    string add;
    if (a > c) {
      ans = "4";
      add = "74";
      --a;
    } else {
      ans = "7";
      add = "47";
      --b;
    }
    for (int i = 0; i < (int)(c); ++i) {
      ans += add;
      --a, --b;
    }
  } else if (c == d + 1) {
    for (int i = 0; i < (int)(c); ++i) ans += "47";
    a -= c;
    b -= c;
  } else if (d == c + 1) {
    for (int i = 0; i < (int)(d); ++i) ans += "74";
    a -= d;
    b -= d;
  } else {
    cout << -1 << endl;
    return 0;
  }
  if (a < 0 || b < 0) {
    cout << -1 << endl;
    return 0;
  }
  for (int i = 0; i < (int)((int(ans.size()))); ++i) {
    if (ans[i] == '4' && i < 2)
      for (int j = 0; j < (int)(a); ++j) cout << '4';
    if (ans[i] == '7' && i + 2 >= (int(ans.size())))
      for (int j = 0; j < (int)(b); ++j) cout << '7';
    cout << ans[i];
  }
  cout << endl;
}
