#include <bits/stdc++.h>
using namespace std;
long long oup[2001000];
signed main() {
  long long a, b, c, d;
  cin >> a >> b >> c >> d;
  if (abs(c - d) > 1) {
    cout << "-1";
    return 0;
  }
  long long sum;
  long long pos4;
  long long pos7;
  if (c > d) {
    if (a < c || b < c) {
      cout << "-1";
      return 0;
    }
    sum = c * 2;
    a -= c;
    b -= c;
    pos4 = 1;
    pos7 = c * 2;
    for (int i = 1; i <= c * 2; i++) {
      if (i % 2 == 1) {
        oup[i] = 4;
      } else {
        oup[i] = 7;
      }
    }
  } else if (c < d) {
    if (a < d || b < d) {
      cout << "-1";
      return 0;
    }
    sum = d * 2;
    a -= d;
    b -= d;
    pos4 = 2;
    pos7 = d * 2 - 1;
    for (int i = 1; i <= d * 2; i++) {
      if (i % 2 == 1) {
        oup[i] = 7;
      } else {
        oup[i] = 4;
      }
    }
  } else if (c == d) {
    sum = c * 2 + 1;
    if (a > c) {
      a -= c + 1;
      b -= c;
      pos4 = 1;
      pos7 = c * 2;
      for (int i = 1; i <= c * 2 + 1; i++) {
        if (i % 2 == 1) {
          oup[i] = 4;
        } else {
          oup[i] = 7;
        }
      }
    } else if (b > c) {
      a -= c;
      b -= c + 1;
      pos4 = 2;
      pos7 = c * 2 + 1;
      for (int i = 1; i <= c * 2 + 1; i++) {
        if (i % 2 == 1) {
          oup[i] = 7;
        } else {
          oup[i] = 4;
        }
      }
    } else {
      cout << "-1";
      return 0;
    }
  }
  if (a < 0 || b < 0) {
    cout << "-1";
    return 0;
  }
  for (int i = 1; i <= sum; i++) {
    cout << oup[i];
    if (i == pos4) {
      while (a--) {
        cout << "4";
      }
    }
    if (i == pos7) {
      while (b--) {
        cout << "7";
      }
    }
  }
}
