#include <bits/stdc++.h>
using namespace std;
long long int binpow(long long int a, long long int b) {
  long long int res = 1;
  while (b > 0) {
    if (b & 1) res = (res * a);
    a = (a * a);
    b >>= 1;
  }
  return res;
}
long long int gcd(long long int a, long long int b) {
  if (b % a == 0) return a;
  return gcd(b % a, a);
}
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long int j, i, n, t, l, a, b, r, c, h, k, m, maxi, d, x;
  cin >> a >> b >> c >> d;
  if (abs(c - d) > 1) {
    cout << -1;
    return 0;
  }
  if (c > d) {
    if (a < c || b < c) {
      cout << -1;
      return 0;
    }
    while (a - c != 0) {
      cout << "4";
      a--;
    }
    for (j = 0; j < c; j++) {
      cout << "47";
    }
    while (b - c != 0) {
      cout << "7";
      b--;
    }
  } else if (c == d) {
    if (a - c - 1 < 0 || b < c) {
      if (b - c - 1 < 0 || a < c) {
        cout << -1;
        return 0;
      }
      cout << "74";
      c--;
      while (a - c - 1 != 0) {
        cout << 4;
        a--;
      }
      for (j = 0; j < c; j++) cout << "74";
      while (b - c - 1 != 0) {
        cout << 7;
        b--;
      }
      return 0;
    }
    while (a - c - 1 != 0) {
      cout << 4;
      a--;
    }
    for (j = 0; j < c; j++) cout << "47";
    while (b - c != 0) {
      cout << "7";
      b--;
    }
    cout << "4";
  } else {
    if (a < d || b < d) {
      cout << -1;
      return 0;
    }
    cout << "74";
    d--;
    while (a - d - 1 != 0) {
      cout << "4";
      a--;
    }
    for (j = 0; j < d - 1; j++) cout << "74";
    while (b - d - 1 != 0) {
      cout << "7";
      b--;
    }
    cout << "74";
  }
  cerr << '\n'
       << "Time elapsed :" << clock() * 1000.0 / CLOCKS_PER_SEC << " ms\n";
}
