#include <bits/stdc++.h>
using namespace std;
int main() {
  int c4, c7, c47, c74;
  scanf("%d%d%d%d", &c4, &c7, &c47, &c74);
  if (c47 == c74 + 1) {
    int b4 = c47, b7 = c47;
    if (c4 >= b4 && c7 >= b7) {
      for (int i = 0; i <= c4 - b4; ++i) {
        printf("4");
      }
      for (int i = 0; i < c74; ++i) {
        printf("74");
      }
      for (int i = 0; i <= c7 - b7; ++i) {
        printf("7");
      }
      printf("\n");
      return 0;
    }
  }
  if (c47 == c74) {
    int b4 = c47 + 1, b7 = c74;
    if (c4 >= b4 && c7 >= b7) {
      for (int i = 0; i <= c4 - b4; ++i) {
        printf("4");
      }
      for (int i = 0; i < c74 - 1; ++i) {
        printf("74");
      }
      for (int i = 0; i <= c7 - b7; ++i) {
        printf("7");
      }
      printf("4\n");
      return 0;
    }
  }
  if (c47 == c74) {
    int b4 = c47, b7 = c74 + 1;
    if (c4 >= b4 && c7 >= b7) {
      printf("7");
      --c74, --c7, --b7;
      for (int i = 0; i <= c4 - b4; ++i) {
        printf("4");
      }
      for (int i = 0; i < c74; ++i) {
        printf("74");
      }
      for (int i = 0; i <= c7 - b7; ++i) {
        printf("7");
      }
      printf("\n");
      return 0;
    }
  }
  if (c74 == c47 + 1) {
    int b4 = c47 + 1, b7 = c74;
    if (c4 >= b4 && c7 >= b7) {
      printf("7");
      --c74, --c7, --b7;
      for (int i = 0; i <= c4 - b4; ++i) {
        printf("4");
      }
      for (int i = 0; i < c74 - 1; ++i) {
        printf("74");
      }
      for (int i = 0; i <= c7 - b7; ++i) {
        printf("7");
      }
      printf("4\n");
      return 0;
    }
  }
  printf("-1\n");
  return 0;
}
