#include <bits/stdc++.h>
using namespace std;
const long long M = 2e5 + 10, oo = 1e9 + 7;
vector<long long> va, vb, fc(M, 0), tcnt(M, 0), cnt(M, 0);
vector<pair<long long, long long> > st;
map<long long, long long> en, dc;
long long dp[40][40];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long a, b, c, d;
  string sa = "4", sb = "7", sc = "47", sd = "74", ans = "", tmp = "";
  cin >> a >> b >> c >> d;
  if (abs(c - d) > 1 || a < max(c, d) || b < max(c, d)) {
    cout << "-1" << endl;
  } else {
    if (c >= d) {
      for (long long i = 0; i < c; i++) ans += sc;
      for (long long i = 0; i < b - c; i++) ans += sb;
    }
    if (c > d) {
      tmp = "";
      for (long long i = 0; i < a - c; i++) tmp += sa;
      tmp += ans;
      ans = tmp;
    }
    if (c == d) {
      tmp = "";
      if (a > c) {
        for (long long i = 0; i < a - c - 1; i++) {
          tmp += sa;
        }
        tmp = tmp + ans + sa;
        ans = tmp;
      } else if (b > c) {
        ans.erase(ans.size() - 1, 1);
        tmp = sb + ans;
        ans = tmp;
      } else {
        cout << "-1" << endl;
        return 0;
      }
    }
    if (c < d) {
      for (long long i = 0; i < d - 1; i++) ans += sd;
      if (b > d)
        for (long long i = 0; i < b - d; i++) {
          ans.erase(ans.size() - 1, 1);
          ans += sb;
          ans += sa;
        }
      if (a > d) {
        tmp = "";
        for (int i = 0; i < a - d; i++) tmp += sa;
        tmp += ans;
        ans = tmp;
      }
      tmp = sd + ans;
      ans = tmp;
    }
    cout << ans << endl;
  }
  return 0;
}
