#include <bits/stdc++.h>
using namespace std;
int a[4];
void fail() {
  printf("-1");
  exit(0);
}
string s;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  for (auto i = 0; i != 4; i++) scanf("%d", &a[i]);
  if (abs(a[2] - a[3]) >= 2) {
    printf("-1");
    return 0;
  }
  if (a[2] > a[3]) {
    if (a[1] < a[2]) fail();
    if (a[0] < a[3] + 1) fail();
    for (auto i = 0; i != a[0] - a[3]; i++) printf("4");
    a[0] = a[3];
    int b7 = a[2];
    int _c = 1;
    while (a[0] + a[1] > 0) {
      if (_c) {
        b7--;
        printf("7");
        a[1]--;
        if (b7 == 0)
          while (a[1] > 0) {
            printf("7");
            a[1]--;
          }
      } else {
        printf("4");
        a[0]--;
      }
      _c = 1 - _c;
    }
    return 0;
  } else if (a[2] < a[3]) {
    if (a[0] < a[3]) fail();
    if (a[1] < a[2] + 1) fail();
    int _c = 1;
    printf("7");
    a[1]--;
    for (auto i = 0; i != a[0] - (a[3] - 1); i++) printf("4");
    a[0] = (a[3] - 1);
    int b7 = a[2];
    while (a[0] + a[1] > 0) {
      if (_c) {
        b7--;
        printf("7");
        a[1]--;
        if (b7 == 0)
          while (a[1] > 0) {
            printf("7");
            a[1]--;
          }
      } else {
        printf("4");
        a[0]--;
      }
      _c = 1 - _c;
    }
    return 0;
  }
  if (a[1] < a[2] || a[0] < a[3] + 1) {
    if (a[0] < a[3]) fail();
    if (a[1] < a[2] + 1) fail();
    int _c = 1;
    printf("7");
    a[1]--;
    for (auto i = 0; i != a[0] - (a[3] - 1); i++) printf("4");
    a[0] = (a[3] - 1);
    int b7 = a[2];
    while (a[0] + a[1] > 0) {
      if (_c) {
        b7--;
        printf("7");
        a[1]--;
        if (b7 == 0)
          while (a[1] > 0) {
            printf("7");
            a[1]--;
          }
      } else {
        printf("4");
        a[0]--;
      }
      _c = 1 - _c;
    }
  } else {
    for (auto i = 0; i != a[0] - a[3]; i++) printf("4");
    a[0] = a[3];
    int b7 = a[2];
    int _c = 1;
    while (a[0] + a[1] > 0) {
      if (_c) {
        b7--;
        printf("7");
        a[1]--;
        if (b7 == 0)
          while (a[1] > 0) {
            printf("7");
            a[1]--;
          }
      } else {
        printf("4");
        a[0]--;
      }
      _c = 1 - _c;
    }
  }
  return 0;
}
