#include <bits/stdc++.h>
using namespace std;
const long long N = 2e2 + 5, K = 20, mod = 1000000007, MOD = 1000000007,
                INF = LLONG_MAX / 2;
void solve() {
  long long a, b, c, d;
  cin >> a >> b >> c >> d;
  string s;
  if (abs(c - d) > 1) {
    cout << -1 << endl;
    return;
  }
  string prev, suff;
  if (c <= d) {
    for (long long i = 0; i < c; i++) s += "47";
    long long f = c, sv = c;
    if (d - c && (a - f <= 0 || b - sv <= 0)) {
      cout << -1 << endl;
      return;
    }
    if (c == d && (a - f == 0 && b - sv == 0)) {
      cout << -1 << endl;
      return;
    }
    if (a < f || b < sv) {
      cout << -1 << endl;
      return;
    }
    if (d - c) {
      prev = "";
      while (f < a - 1) {
        f++;
        prev += '4';
      }
      s = prev + s;
      suff = "";
      while (sv < b - 1) {
        sv++;
        suff += '7';
      }
      s += suff;
      s = '7' + s + '4';
    } else {
      if (a - f) {
        suff = "";
        while (sv < b) {
          sv++;
          suff += '7';
        }
        s += suff;
        s += '4';
        f++;
        prev = "";
        while (f < a) {
          prev += '4';
          f++;
        }
        s = prev + s;
      } else {
        suff = "";
        while (sv < b - 1) {
          sv++;
          suff += '7';
        }
        s += suff;
        s = '7' + s;
      }
    }
  } else {
    for (long long i = 0; i < d; i++) s += "74";
    long long f = d, sv = d;
    if (a - f <= 0 || b - sv <= 0) {
      cout << -1 << endl;
      return;
    }
    suff = "";
    while (sv < b) {
      sv++;
      suff += '7';
    }
    s = s + suff;
    prev = "";
    while (f < a) {
      f++;
      prev += '4';
    }
    s = prev + s;
  }
  cout << s << endl;
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long TESTS = 1;
  while (TESTS--) {
    solve();
  }
  return 0;
}
