#include <bits/stdc++.h>
using namespace std;
vector<int> a;
string build(int cnt1, int cnt2) {
  if (cnt1 == cnt2) {
    string ret = "";
    if (a[0] >= cnt1 + 1) {
      for (int i = 0; i < cnt1; ++i) ret += "47", a[0]--, a[1]--;
      ret += "4", a[0]--;
      return ret;
    } else {
      for (int i = 0; i < cnt1; ++i) ret += "74", a[0]--, a[1]--;
      ret += "7", a[1]--;
      return ret;
    }
  }
  string ret = "";
  if (cnt1 > cnt2) {
    for (int i = 0; i < cnt1; ++i) ret += "47", a[0]--, a[1]--;
  } else {
    for (int i = 0; i < cnt2; ++i) ret += "74", a[0]--, a[1]--;
  }
  return ret;
}
int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  a.resize(4);
  for (int &x : a) cin >> x;
  if (abs(a[2] - a[3]) > 1) {
    cout << "-1\n";
    return 0;
  }
  int mx1 = 0, mx2 = 0;
  string s = "";
  if (a[0] > a[1]) {
    int cnt_4 = a[0], cnt_7 = a[1];
    while (cnt_4 && cnt_7) {
      s += "4";
      cnt_4--;
      s += "7";
      cnt_7--;
    }
    if (cnt_4) s += "4";
  } else {
    int cnt_4 = a[0], cnt_7 = a[1];
    while (cnt_4 && cnt_7) {
      s += "7";
      cnt_7--;
      s += "4";
      cnt_4--;
    }
    if (cnt_7) s += "7";
  }
  for (int i = 0; i < (int)s.size(); ++i) {
    if (s[i] == '4' && s[i + 1] == '7')
      mx1++;
    else if (s[i] == '7' && s[i + 1] == '4')
      mx2++;
  }
  if (a[2] <= mx1 && a[3] <= mx2) {
    string ans = build(a[2], a[3]);
    int lst_7 = -1;
    for (int i = 0; i < (int)ans.size(); ++i)
      if (ans[i] == '7') lst_7 = i;
    for (int i = 0; i < (int)ans.size(); ++i) {
      if (ans[i] == '4' && a[0]) {
        while (a[0]) cout << '4', a[0]--;
      }
      if (i == lst_7 && a[1]) {
        while (a[1]) cout << '7', a[1]--;
      }
      cout << ans[i];
    }
    cout << '\n';
    return 0;
  }
  swap(mx1, mx2);
  if (a[2] <= mx1 && a[3] <= mx2) {
    string ans = build(a[2], a[3]);
    int lst_7 = -1;
    for (int i = 0; i < (int)ans.size(); ++i)
      if (ans[i] == '7') lst_7 = i;
    for (int i = 0; i < (int)ans.size(); ++i) {
      if (ans[i] == '4' && a[0]) {
        while (a[0]) cout << '4', a[0]--;
      }
      if (i == lst_7 && a[1]) {
        while (a[1]) cout << '7', a[1]--;
      }
      cout << ans[i];
    }
    cout << '\n';
    return 0;
  }
  cout << "-1\n";
}
