#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9 + 5;
const int MAXN = 1005;
const int MOD = 1e9 + 7;
const double eps = 1e-8;
const double PI = acos(-1.0);
long long gcd(long long a, long long b) { return b == 0 ? a : gcd(b, a % b); }
long long ppow(long long a, long long b) {
  long long res = 1;
  for (int i = 1; i <= b; i++) res *= a;
  return res;
}
long long quick_mod(long long a, long long b, long long c) {
  long long ans = 1;
  while (b) {
    if (b % 2 == 1) ans = (ans * a) % c;
    b /= 2;
    a = (a * a) % c;
  }
  return ans;
}
int main() {
  int num4, num7, num47, num74;
  scanf("%d%d%d%d", &num4, &num7, &num47, &num74);
  if (abs(num47 - num74) >= 2) {
    printf("-1\n");
    return 0;
  } else if (num47 == num74) {
    if (num4 < 2 && num7 < 2) {
      printf("-1\n");
      return 0;
    }
    if (num4 > num47 && num7 >= num47) {
      num4 = num4 - num47 - 1;
      num7 = num7 - num47;
      for (int i = 1; i <= num4; i++) printf("4");
      for (int i = 1; i <= num47; i++) printf("47");
      for (int i = 1; i <= num7; i++) printf("7");
      printf("4\n");
      return 0;
    } else if (num7 > num47 && num4 >= num47) {
      num7 = num7 - 1 - num47;
      printf("7");
      for (int i = 1; i <= num47; i++) printf("47");
      for (int i = 1; i <= num7; i++) printf("7");
      printf("\n");
      return 0;
    } else {
      printf("-1\n");
      return 0;
    }
  } else if (num47 > num74) {
    num4 = num4 - num47;
    num7 = num7 - num47;
    if (num4 < 0 || num7 < 0) {
      printf("-1\n");
      return 0;
    }
    for (int i = 1; i <= num4; i++) printf("4");
    for (int i = 1; i <= num47; i++) printf("47");
    for (int i = 1; i <= num7; i++) printf("7");
    printf("\n");
  } else {
    num4 = num4 - num74;
    num7 = num7 - num74;
    if (num4 < 0 || num7 < 0) {
      printf("-1\n");
      return 0;
    }
    printf("7");
    for (int i = 1; i <= num4; i++) printf("4");
    for (int i = 1; i <= num47; i++) printf("47");
    for (int i = 1; i <= num7; i++) printf("7");
    printf("4\n");
  }
}
