#include <bits/stdc++.h>
using namespace std;
template <typename T>
string tostr(const T& t) {
  ostringstream os;
  os << t;
  return os.str();
}
string solve(int cnt4, int cnt7, int cnt47, int cnt74) {
  int p1, p2;
  string res = "";
  if (abs(cnt47 - cnt74) > 1) return "-1";
  if (cnt47 == cnt74) {
    if (cnt47 == 1) {
      if (cnt4 > 1) {
        res += "474";
        cnt4 -= 2;
        cnt7--;
      } else {
        res += "747";
        cnt4--;
        cnt7 -= 2;
      }
    } else {
      for (int i = 0; i < cnt47; ++i) {
        res += "47";
        cnt4--;
        cnt7--;
        if (i > 0) cnt74--;
      }
      for (int i = 0; i < cnt74; ++i) {
        if (i > 0) {
          res += "74";
          cnt4--;
          cnt7--;
        } else {
          if (cnt4 - 1 >= 0) {
            cnt4--;
            res += "4";
          } else if (cnt7 - 1 >= 0) {
            cnt7--;
            res = "7" + res;
          } else {
            return "-1";
          }
        }
      }
    }
  } else if (cnt47 > cnt74) {
    for (int i = 0; i < cnt47; ++i) {
      res += "47";
      cnt4--;
      cnt7--;
    }
  } else {
    for (int i = 0; i < cnt74; ++i) {
      res += "74";
      cnt4--;
      cnt7--;
    }
  }
  if (cnt4 < 0 || cnt7 < 0) return "-1";
  string rem4 = string(cnt4, '4');
  string rem7 = string(cnt7, '7');
  p1 = res.find("4");
  res = res.substr(0, p1) + rem4 + res.substr(p1);
  p2 = res.rfind("7");
  res = res.substr(0, p2) + rem7 + res.substr(p2);
  return res;
}
int main(int argc, char* argv[]) {
  string res = "";
  int c4, c7, c47, c74;
  cin >> c4 >> c7 >> c47 >> c74;
  cout << solve(c4, c7, c47, c74) << endl;
  return 0;
}
