#include <bits/stdc++.h>
using namespace std;
int n, m, p, q;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> m >> p >> q;
  if (abs(p - q) >= 2 || p > (min(m, n)) || q > min(m, n) ||
      (!p && !q && n && m)) {
    cout << "-1";
    return 0;
  } else if (!p && !q && !m && !n)
    return 0;
  else {
    string s = "";
    if (p == q) {
      if (m == n && n == p) {
        cout << "-1";
        return 0;
      } else {
        bool ok = 1;
        for (int i = 1; i <= p; ++i) {
          s += "47";
        }
        s += '4';
        m -= p;
        n -= (p + 1);
        if (m < 0 || n < 0) {
          ok = 0;
          m += p;
          n += (p + 1);
          s = "";
        }
        if (ok) {
          for (int i = 0; i < s.size(); ++i) {
            cout << s[i];
            if (i == 0 && n)
              for (int j = 1; j <= n; ++j) cout << 4;
            if (i == s.size() - 2 && m)
              for (int j = 1; j <= m; ++j) cout << 7;
          }
          return 0;
        } else {
          for (int i = 1; i <= p; ++i) {
            s += "74";
          }
          s += '7';
          m -= (p + 1);
          n -= p;
          if (m < 0 || n < 0) {
            cout << "-1";
            return 0;
          }
          for (int i = 0; i < s.size(); ++i) {
            cout << s[i];
            if (i == 0 && n)
              for (int j = 1; j <= n; ++j) cout << 4;
            if (i == s.size() - 2 && m)
              for (int j = 1; j <= m; ++j) cout << 7;
          }
          return 0;
        }
        cout << -1;
        return 0;
      }
    } else {
      string s = "";
      if (p > q) {
        for (int i = 1; i <= p; ++i) s += "47";
        m -= p;
        n -= p;
        if (m < 0 || n < 0) {
          cout << "-1";
          return 0;
        }
        for (int i = 0; i < s.size(); ++i) {
          cout << s[i];
          if (!i && n)
            for (int j = 1; j <= n; ++j) cout << 4;
          if (i == s.size() - 1 && m)
            for (int j = 1; j <= m; ++j) cout << 7;
        }
        return 0;
      } else {
        for (int i = 1; i <= q; ++i) s += "74";
        m -= q;
        n -= q;
        if (m < 0 || n < 0) {
          cout << "-1";
          return 0;
        }
        for (int i = 0; i < s.size(); ++i) {
          cout << s[i];
          if (i == 1 && n)
            for (int j = 1; j <= n; ++j) cout << 4;
          if (i == s.size() - 2 && m)
            for (int j = 1; j <= m; ++j) cout << 7;
        }
        return 0;
      }
    }
  }
}
