#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  string s = "";
  long long int a, b, c, d;
  cin >> a >> b >> c >> d;
  if (abs(c - d) > 1)
    cout << -1 << '\n';
  else {
    long long int cnt4 = 0;
    long long int cnt7 = 0;
    if (c == d) {
      if (c + 1 <= a) {
        cnt7 += c;
        cnt4 += c + 1;
        if (cnt4 > a || cnt7 > b)
          cout << -1 << '\n';
        else {
          a -= cnt4;
          b -= cnt7;
          for (long long int j = 1; j <= a; j++) cout << "4";
          for (long long int j = 1; j <= c; j++) cout << "47";
          for (long long int j = 1; j <= b; j++) cout << "7";
          cout << "4" << '\n';
        }
      } else {
        cnt7 += c + 1;
        cnt4 += c;
        if (cnt4 > a || cnt7 > b)
          cout << -1 << '\n';
        else {
          a -= cnt4;
          b -= cnt7;
          if (c > 0) {
            cout << "7";
            for (long long int j = 1; j <= a; j++) cout << "4";
            cout << "4";
          }
          for (long long int j = 1; j < c; j++) cout << "74";
          for (long long int j = 1; j <= b; j++) cout << "7";
          cout << "7" << '\n';
        }
      }
    } else if (c > d) {
      cnt4 += c;
      cnt7 += c;
      if (cnt4 > a || cnt7 > b)
        cout << -1 << '\n';
      else {
        a -= cnt4;
        b -= cnt7;
        for (long long int j = 1; j <= a; j++) cout << "4";
        for (long long int j = 1; j <= c; j++) cout << "47";
        for (long long int j = 1; j <= b; j++) cout << "7";
      }
    } else {
      cnt4 += d;
      cnt7 += d;
      if (cnt4 > a || cnt7 > b)
        cout << -1 << '\n';
      else {
        a -= cnt4;
        b -= cnt7;
        if (d > 0) {
          cout << "7";
          for (long long int j = 1; j <= a; j++) cout << "4";
          cout << "4";
        }
        d--;
        for (long long int j = 1; j < d; j++) cout << "74";
        for (long long int j = 1; j <= b; j++) cout << "7";
        cout << "74" << '\n';
      }
    }
  }
  return 0;
}
