#include <bits/stdc++.h>
using namespace std;
const long double PI = 2 * acos(0);
const long double eps = 1e-15;
const int inf = 1e9 + 7;
const long long Linf = (long long)1e18 + 7;
const int MOD = 1e9 + 7;
const int LMAX = 1e6 + 7;
const int MAX = 1e5 + 7;
const int BASE = 1e9 + 7;
int dx[] = {-1, 0, 0, 1};
int dy[] = {0, -1, 1, 0};
int main() {
  ios::sync_with_stdio(false);
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  if (c == d) {
    a -= c + 1;
    b -= c;
    if (a >= 0 && b >= 0) {
      for (int i = (1); i <= (a); i++) {
        cout << 4;
      }
      for (int i = (1); i <= (c); i++) {
        cout << 47;
      }
      for (int i = (1); i <= (b); i++) {
        cout << 7;
      }
      cout << 4;
    } else {
      a += c + 1;
      b += c;
      a -= c;
      b -= c + 1;
      if (a >= 0 && b >= 0) {
        cout << 7;
        for (int i = (1); i <= (a); i++) cout << 4;
        for (int i = (1); i <= (c); i++) cout << 47;
        for (int i = (1); i <= (b); i++) cout << 7;
      } else
        cout << -1;
    }
  } else if (c == d + 1) {
    a -= c;
    b -= c;
    if (a >= 0 && b >= 0) {
      for (int i = (1); i <= (a); i++) {
        cout << 4;
      }
      for (int i = (1); i <= (c); i++) {
        cout << 47;
      }
      for (int i = (1); i <= (b); i++) {
        cout << 7;
      }
    } else
      cout << -1;
  } else if (d == c + 1) {
    a -= d;
    b -= d;
    if (a >= 0 && b >= 0) {
      cout << 7;
      for (int i = (1); i <= (a); i++) {
        cout << 4;
      }
      for (int i = (1); i <= (c); i++) {
        cout << 47;
      }
      for (int i = (1); i <= (b); i++) {
        cout << 7;
      }
      cout << 4;
    } else
      cout << -1;
  } else
    cout << -1;
}
