#include <bits/stdc++.h>
const long long MOD = 1e9 + 7;
const long long MAXN = 4e6 + 1;
using namespace std;
long long readInt() {
  bool minus1 = false;
  long long result = 0;
  char ch;
  ch = getchar();
  while (true) {
    if (ch == '-') break;
    if (ch >= '0' && ch <= '9') break;
    ch = getchar();
  }
  if (ch == '-')
    minus1 = true;
  else
    result = ch - '0';
  while (true) {
    ch = getchar();
    if (ch<'0' | ch> '9') break;
    result = result * 10 + (ch - '0');
  }
  if (minus1)
    return -result;
  else
    return result;
}
int used[MAXN];
int main() {
  int a1 = readInt(), a2 = readInt(), a3 = readInt(), a4 = readInt();
  if (abs(a3 - a4) > 1) {
    cout << -1;
    return 0;
  }
  string s1 = "47";
  string s2 = "74";
  string ans = "";
  if (a3 == a4) {
    for (int i = 1; i <= a3; i++) {
      ans += s1;
      ans += s2;
    }
  } else {
    if (a3 - 1 == a4) {
      for (int i = 1; i <= a4; i++) {
        ans += s1;
        ans += s2;
      }
      ans += s1;
    } else {
      for (int i = 1; i <= a3; i++) {
        ans += s2;
        ans += s1;
      }
      ans += s2;
    }
  }
  int f = 0;
label:
  f++;
  int count_4 = 0;
  int count_7 = 0;
  for (int i = 0; i < ans.size(); i++) {
    count_4 += (ans[i] == '4');
    count_7 += (ans[i] == '7');
  }
  int dif_4 = count_4 - a1;
  int dif_7 = count_7 - a2;
  for (int i = 0; i < ans.size(); i++) {
    if (i && ans[i] == ans[i - 1] && ans[i] == '4') {
      used[i] = 1;
      dif_4--;
    }
    if (i && ans[i] == ans[i - 1] && ans[i] == '7') {
      used[i] = 1;
      dif_7--;
    }
  }
  if (dif_4 > 0 || dif_7 > 0) {
    if (a3 == a4 && f == 1) {
      swap(s1, s2);
      ans = "";
      for (int i = 1; i <= a3; i++) {
        ans += s1;
        ans += s2;
      }
      goto label;
    }
    cout << -1;
    return 0;
  }
  if (dif_4 < 0 || dif_7 < 0) {
    int in_4 = -1;
    int in_7 = -1;
    for (int i = 0; i < ans.size(); i++) {
      if (!used[i]) {
        if (ans[i] == '4') {
          if (in_4 == -1) in_4 = i;
        } else {
          in_7 = i;
        }
      }
    }
    for (int i = 0; i < ans.size(); i++) {
      if (!used[i]) {
        cout << ans[i];
        if (i == in_4) {
          for (int j = 1; j <= -dif_4; j++) {
            cout << 4;
          }
        }
        if (i == in_7) {
          for (int j = 1; j <= -dif_7; j++) {
            cout << 7;
          }
        }
      }
    }
  } else {
    for (int i = 0; i < ans.size(); i++) {
      if (!used[i]) {
        cout << ans[i];
      }
    }
  }
  return 0;
}
