#include <bits/stdc++.h>
int a, b, c, d, n;
char s[4 << 20];
void output() {
  for (int i = 0; i < n; ++i)
    if (s[i] == '4')
      a--;
    else
      b--;
  for (int i = 0; i < n; ++i)
    if (s[i] == '4') {
      while (a) {
        printf("4");
        a--;
      }
      printf("4");
    } else {
      while ((i + 2 >= n) && b) {
        printf("7");
        b--;
      }
      printf("7");
    }
  printf("\n");
  exit(0);
}
void look(char c4, char c7, int a, int b, int c, int d) {
  n = 0;
  while (c) {
    if (n) d--;
    s[n++] = c4;
    s[n++] = c7;
    a--;
    b--;
    c--;
  }
  if (d > 0) {
    s[n++] = c4;
    a--;
    d--;
  }
  if ((a < 0) || (b < 0) || (c != 0) || (d != 0)) return;
  output();
}
int main() {
  scanf("%d%d%d%d", &a, &b, &c, &d);
  look('4', '7', a, b, c, d);
  look('7', '4', b, a, d, c);
  printf("-1\n");
  return 0;
}
