#include <bits/stdc++.h>
using namespace std;
int c4, c7, c47, c74;
int solve() {
  int cnt = (c47 + c74 + 1) / 2;
  if (abs(c47 - c74) > 1) return -1;
  if (c47 > c74) {
    if (c4 < cnt || c7 < cnt) return -1;
    for (int i = (1), _b = (c4 - cnt); i <= _b; ++i) cout << '4';
    for (int i = (1), _b = (cnt); i <= _b; ++i) cout << "47";
    for (int i = (1), _b = (c7 - cnt); i <= _b; ++i) cout << '7';
  } else if (c47 < c74) {
    if (c4 < cnt || c7 < cnt) return -1;
    if (cnt == 1) {
      for (int i = (1), _b = (c7); i <= _b; ++i) cout << 7;
      for (int i = (1), _b = (c4); i <= _b; ++i) cout << 4;
    } else {
      cout << '7';
      for (int i = (1), _b = (c4 - cnt + 1); i <= _b; ++i) cout << '4';
      for (int i = (2), _b = (cnt - 1); i <= _b; ++i) cout << "74";
      for (int i = (1), _b = (c7 - cnt + 1); i <= _b; ++i) cout << '7';
      cout << '4';
    }
  } else {
    if (c4 < cnt || c7 < cnt) return -1;
    if (c4 > cnt) {
      for (int i = (1), _b = (c4 - cnt - 1); i <= _b; ++i) cout << 4;
      for (int i = (1), _b = (cnt); i <= _b; ++i) cout << 47;
      for (int i = (1), _b = (c7 - cnt); i <= _b; ++i) cout << 7;
      cout << 4;
    } else if (c7 > cnt) {
      cout << 7;
      for (int i = (1), _b = (c4 - cnt); i <= _b; ++i) cout << 4;
      for (int i = (1), _b = (cnt); i <= _b; ++i) cout << 47;
      for (int i = (1), _b = (c7 - cnt - 1); i <= _b; ++i) cout << 7;
    } else
      return -1;
  }
  cout << endl;
  return 0;
}
int main() {
  cin >> c4 >> c7 >> c47 >> c74;
  if (solve()) cout << "-1" << endl;
  return 0;
}
