#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:167772160")
using namespace std;
const double pi = 2 * acos(0.0);
string ans, w;
int k1, k2, k3, k4, i, j, k, len, l1, l2;
bool OK() {
  int l1 = 0, l2 = 0, l3 = 0, l4 = 0, i;
  for (i = 0; i <= len - 1; ++i) {
    if (ans[i] == '4') l1++;
    if (ans[i] == '7') l2++;
    if (i < len - 1) {
      if (ans[i] == '4' && ans[i + 1] == '7') l3++;
      if (ans[i] == '7' && ans[i + 1] == '4') l4++;
    }
  }
  return (l1 == k1 && l2 == k2 && l3 == k3 && l4 == k4);
}
void pr() {
  int i;
  for (i = 0; i <= len - 1; ++i) cout << ans[i];
  cout << endl;
}
int main() {
  cin >> k1 >> k2 >> k3 >> k4;
  len = k1 + k2;
  ans = "";
  l1 = l2 = 0;
  for (i = 1; i <= k3; ++i) {
    ans += "47";
    l1++;
    l2++;
  }
  w = "";
  if (k3 == k4) {
    bool ok;
    if (l1 < k1)
      ok = true;
    else
      ok = false;
    if (ok) {
      l1++;
      for (i = 1; i <= k1 - l1; ++i) w += "4";
      for (i = 1; i <= k3; ++i) w += "47";
      for (i = 1; i <= k2 - l2; ++i) w += "7";
      w += "4";
      ans = w;
    } else {
      l2++;
      w = "";
      for (i = 1; i <= k1 - l1; ++i) w += "4";
      w += "7";
      for (i = 1; i <= k3; ++i) w += "47";
      for (i = 1; i <= k2 - l2; ++i) w += "7";
      ans = w;
    }
  } else if (k3 > k4) {
    w = "";
    for (i = 1; i <= k1 - l1; ++i) w += "4";
    for (i = 1; i <= k3; ++i) w += "47";
    for (i = 1; i <= k2 - l2; ++i) w += "7";
    ans = w;
  } else {
    ans = "7" + ans;
    l2++;
    ans += "4";
    l1++;
    w = "7";
    for (i = 1; i <= k1 - l1; ++i) w += "4";
    for (i = 1; i <= k3; ++i) w += "47";
    for (i = 1; i <= k2 - l2; ++i) w += "7";
    w += "4";
    ans = w;
  }
  if (OK())
    pr();
  else
    cout << "-1" << endl;
}
