#include <bits/stdc++.h>
using namespace std;
int total;
char ans[2097152];
char buf[2097152];
int n4, n7, n47, n74;
void compare(int buflen) {
  if (buflen != total) return;
  int nn4 = n4;
  int nn7 = n7;
  int nn47 = n47;
  int nn74 = n74;
  for (int i = 0; i < buflen; i++) {
    if (buf[i] == '4') {
      nn4--;
      if (buf[i + 1] == '7') {
        nn47--;
      }
    }
    if (buf[i] == '7') {
      nn7--;
      if (buf[i + 1] == '4') {
        nn74--;
      }
    }
  }
  if (nn4 || nn7 || nn47 || nn74) return;
  if (ans[0] == '\0' || strcmp(ans, buf) > 0) {
    strcpy(ans, buf);
  }
}
void try47(int n4, int n7, int n47, int n74) {
  if (n47 != n74 && n47 != n74 + 1) return;
  if (n47 == n74) {
    n4 -= n47 + 1;
    n7 -= n47;
    if (n4 < 0 || n7 < 0) return;
    int buflen = 0;
    for (int i = 0; i < n4; i++) {
      buf[buflen++] = '4';
    }
    for (int i = 0; i < n47; i++) {
      buf[buflen++] = '4';
      buf[buflen++] = '7';
    }
    for (int i = 0; i < n7; i++) {
      buf[buflen++] = '7';
    }
    buf[buflen++] = '4';
    buf[buflen] = '\0';
    compare(buflen);
  } else {
    n4 -= n47;
    n7 -= n47;
    if (n4 < 0 || n7 < 0) return;
    int buflen = 0;
    for (int i = 0; i < n4; i++) {
      buf[buflen++] = '4';
    }
    for (int i = 0; i < n47; i++) {
      buf[buflen++] = '4';
      buf[buflen++] = '7';
    }
    for (int i = 0; i < n7; i++) {
      buf[buflen++] = '7';
    }
    buf[buflen] = '\0';
    compare(buflen);
  }
}
void try74(int n4, int n7, int n47, int n74) {
  if (n47 != n74 && n74 != n47 + 1) return;
  if (n47 == n74) {
    n7 -= n74 + 1;
    n4 -= n74;
    if (n4 < 0 || n7 < 0) return;
    int buflen = 0;
    for (int i = 0; i < n74; i++) {
      buf[buflen++] = '7';
      buf[buflen++] = '4';
      if (i == 0) {
        for (int j = 0; j < n4; j++) {
          buf[buflen++] = '4';
        }
      }
    }
    buf[buflen++] = '7';
    for (int j = 0; j < n7; j++) {
      buf[buflen++] = '7';
    }
    buf[buflen] = '\0';
    compare(buflen);
  } else {
    n4 -= n74;
    n7 -= n74;
    if (n4 < 0 || n7 < 0) return;
    int buflen = 0;
    for (int i = 0; i < n74; i++) {
      buf[buflen++] = '7';
      if (i + 1 == n74) {
        for (int j = 0; j < n7; j++) {
          buf[buflen++] = '7';
        }
      }
      buf[buflen++] = '4';
      if (i == 0) {
        for (int j = 0; j < n4; j++) {
          buf[buflen++] = '4';
        }
      }
    }
    buf[buflen] = '\0';
    compare(buflen);
  }
}
int main() {
  scanf("%d%d%d%d", &n4, &n7, &n47, &n74);
  total = n4 + n7;
  if (n47 - n74 < -1 || n47 - n74 > 1) {
    printf("-1\n");
    return 0;
  }
  try47(n4, n7, n47, n74);
  try74(n4, n7, n47, n74);
  if (ans[0] == '\0') {
    printf("-1\n");
    return 0;
  } else {
    printf("%s\n", ans);
  }
  return 0;
}
