#include <bits/stdc++.h>
const double PI = acos(-1);
const double EPS = 1e-12;
const int MOD = 1e9 + 7;
const int INF = 1 << 30;
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  if (abs(c - d) > 1)
    cout << "-1" << endl;
  else if (a < max(c, d) || b < max(c, d))
    cout << "-1" << endl;
  else if (a == b && a == c && a == d)
    cout << "-1" << endl;
  else {
    if (c > d) {
      for (int i = 1; i <= a - c; i += 1) cout << "4";
      for (int i = 1; i <= c; i += 1) cout << "47";
      for (int i = 1; i <= b - c; i += 1) cout << "7";
    } else if (c < d) {
      for (int i = 1; i <= d - 1; i += 1) {
        cout << "74";
        if (i == 1)
          for (int i = 1; i <= a - d; i += 1) cout << "4";
      }
      for (int i = 1; i <= b - d + 1; i += 1) cout << "7";
      cout << "4" << endl;
    } else {
      if (a > b) {
        for (int i = 1; i <= a - c - 1; i += 1) cout << "4";
        for (int i = 1; i <= c; i += 1) cout << "47";
        for (int i = 1; i <= b - d; i += 1) cout << "7";
        cout << "4";
      } else if (a < b) {
        if (a > max(c, d)) {
          for (int i = 1; i <= a - max(c, d) - 1; i += 1) cout << "4";
          for (int i = 1; i <= c; i += 1) cout << "47";
          for (int i = 1; i <= b - d; i += 1) cout << "7";
          cout << "4";
        } else {
          for (int i = 1; i <= d; i += 1) {
            cout << "74";
            if (a <= max(c, d) && i == d)
              for (int i = 1; i <= b - d; i += 1) cout << "7";
          }
        }
      } else if (a == b) {
        for (int i = 1; i <= a - c - 1; i += 1) cout << "4";
        for (int i = 1; i <= c; i += 1) cout << "47";
        for (int i = 1; i <= b - c - 1; i += 1) cout << "7";
        for (int i = 1; i <= d - c + 1; i += 1) cout << "74";
      }
    }
  }
}
