#include <bits/stdc++.h>
using namespace std;
const double pi = acos(-1.0);
const int mod = 1000000007;
const int inf = 0x3f3f3f3f;
const int maxn = 200005;
void task() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  if (abs(c - d) > 1 or min(a, b) < max(c, d)) {
    cout << -1 << "\n";
  } else {
    if (c > d) {
      for (int i = 0; i < a - d; i++) cout << 4;
      for (int i = 0; i < d; i++) cout << 74;
      for (int i = 0; i < b - d; i++) cout << 7;
    } else if (c < d) {
      cout << 7;
      for (int i = 0; i < a - c; i++) cout << 4;
      for (int i = 0; i < c - 1; i++) cout << 74;
      for (int i = 0; i < b - c; i++) cout << 7;
      cout << 4;
    } else {
      if (a + b < c + d + 1) {
        puts("-1");
        return;
      }
      for (int i = 0; i < a - c; i++) cout << 4;
      if (a - c > 0) {
        for (int i = 0; i < c - 1; i++) cout << 74;
        for (int i = 0; i < b - c + 1; i++) cout << 7;
        cout << 4;
      } else {
        cout << 7;
        for (int i = 0; i < c; i++) cout << 47;
        for (int i = 0; i < b - 1 - c; i++) cout << 7;
      }
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int T = 1;
  while (T--) {
    task();
  }
  return 0;
}
