#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  int a1, a2, a3, a4;
  cin >> a1 >> a2 >> a3 >> a4;
  if (abs(a3 - a4) > 1) {
    cout << -1;
    return 0;
  }
  list<char> s;
  list<char> s2;
  if (a3 < a4) {
    for (int i = 0; i < a4; i++) {
      s.push_back('7');
      s.push_back('4');
    }
    int sevens = 0;
    int fours = 0;
    for (list<char>::iterator it = s.begin(); it != s.end(); ++it) {
      if (*it == '4') {
        fours++;
      } else {
        sevens++;
      }
    }
    if (fours > a1 || sevens > a2) {
      cout << -1;
      return 0;
    }
    for (list<char>::iterator it = s.begin(); it != s.end(); ++it) {
      if (*it == '4') {
        for (int j = 0; j < a1 - fours; j++) {
          s.insert(it, '4');
        }
        break;
      }
    }
    for (list<char>::iterator it = (--s.end()); it != s.begin(); --it) {
      if (*it == '7') {
        for (int j = 0; j < a2 - sevens; j++) {
          s.insert(it, '7');
        }
        break;
      }
    }
  } else if (a3 == a4) {
    for (int i = 0; i < a3; i++) {
      s.push_back('4');
      s.push_back('7');
    }
    s.push_back('4');
    list<char> s2;
    for (int i = 0; i < a3; i++) {
      s2.push_back('7');
      s2.push_back('4');
    }
    s2.push_back('7');
    int sevens = 0;
    int fours = 0;
    for (list<char>::iterator it = s.begin(); it != s.end(); ++it) {
      if (*it == '4') {
        fours++;
      } else {
        sevens++;
      }
    }
    int sevens2 = 0;
    int fours2 = 0;
    for (list<char>::iterator it = s2.begin(); it != s2.end(); ++it) {
      if (*it == '4') {
        fours2++;
      } else {
        sevens2++;
      }
    }
    if ((fours > a1 || sevens > a2) && (fours2 > a1 || sevens2 > a2)) {
      cout << -1;
      return 0;
    } else {
      if (!(fours > a1 || sevens > a2)) {
        for (list<char>::iterator it = s.begin(); it != s.end(); ++it) {
          if (*it == '4') {
            for (int j = 0; j < a1 - fours; j++) {
              s.insert(it, '4');
            }
            break;
          }
        }
        for (list<char>::iterator it = (--s.end()); it != s.begin(); --it) {
          if (*it == '7') {
            for (int j = 0; j < a2 - sevens; j++) {
              s.insert(it, '7');
            }
            break;
          }
        }
        for (list<char>::iterator it = s.begin(); it != s.end(); ++it) {
          cout << *it;
        }
        return 0;
      } else if (!(fours2 > a1 || sevens2 > a2)) {
        for (list<char>::iterator it = s2.begin(); it != s2.end(); ++it) {
          if (*it == '4') {
            for (int j = 0; j < a1 - fours2; j++) {
              s2.insert(it, '4');
            }
            break;
          }
        }
        for (list<char>::iterator it = (--s2.end()); it != s2.begin(); --it) {
          if (*it == '7') {
            for (int j = 0; j < a2 - sevens2; j++) {
              s2.insert(it, '7');
            }
            break;
          }
        }
        for (list<char>::iterator it = s2.begin(); it != s2.end(); ++it) {
          cout << *it;
        }
        return 0;
      } else {
        cout << -1;
        return 0;
      }
    }
  } else {
    for (int i = 0; i < a3; i++) {
      s.push_back('4');
      s.push_back('7');
    }
    int sevens = 0;
    int fours = 0;
    for (list<char>::iterator it = s.begin(); it != s.end(); ++it) {
      if (*it == '4') {
        fours++;
      } else {
        sevens++;
      }
    }
    if (fours > a1 || sevens > a2) {
      cout << -1;
      return 0;
    }
    for (list<char>::iterator it = s.begin(); it != s.end(); ++it) {
      if (*it == '4') {
        for (int j = 0; j < a1 - fours; j++) {
          s.insert(it, '4');
        }
        break;
      }
    }
    for (list<char>::iterator it = (--s.end()); it != s.begin(); --it) {
      if (*it == '7') {
        for (int j = 0; j < a2 - sevens; j++) {
          s.insert(it, '7');
        }
        break;
      }
    }
  }
  for (list<char>::iterator it = s.begin(); it != s.end(); ++it) {
    cout << *it;
  }
  return 0;
}
