#include <bits/stdc++.h>
using namespace std;
int main() {
  long long a, b, c, d;
  cin >> a >> b >> c >> d;
  if (abs(c - d) > 1) {
    puts("-1");
    return 0;
  }
  bool flag = false;
  int t1 = c, t2 = d;
  if (c >= d) {
    string res = "";
    bool first = true;
    int cnt4 = 0, cnt7 = 0;
    while (c || d) {
      res += '4';
      ++cnt4;
      if (!first) --d;
      if (!c) break;
      ++cnt7;
      res += '7';
      --c;
      first = false;
    }
    int id7 = -1;
    if (cnt7 < b) {
      for (int i = res.size(); i >= 0; --i)
        if (res[i] == '7') {
          id7 = i;
          break;
        }
    } else if (cnt7 > b || c || d) {
      flag = true;
    }
    if (!flag) {
      if (cnt4 <= a) {
        for (int i = cnt4; i < a; ++i) printf("4");
        for (int i = 0; i < res.size(); ++i) {
          if (i == id7)
            for (int j = cnt7; j < b; ++j) printf("7");
          printf("%c", res[i]);
        }
      } else if (cnt4 > a) {
        flag = true;
      }
    }
  } else
    flag = true;
  if (flag) {
    c = t1;
    d = t2;
    string res = "";
    bool first = true;
    int cnt4 = 0, cnt7 = 0;
    while (c || d) {
      res += '7';
      ++cnt7;
      if (!first) --c;
      if (!d) break;
      ++cnt4;
      res += '4';
      --d;
      first = false;
    }
    if (cnt4 > a || c || d) {
      puts("-1");
      return 0;
    }
    int id7 = -1;
    if (cnt7 < b) {
      for (int i = res.size(); i >= 0; --i)
        if (res[i] == '7') {
          id7 = i;
          break;
        }
    } else if (cnt7 > b) {
      puts("-1");
      return 0;
    }
    for (int i = 0; i < res.size(); ++i) {
      if (i == 1)
        for (int j = cnt4; j < a; ++j) printf("4");
      if (i == id7)
        for (int j = cnt7; j < b; ++j) printf("7");
      printf("%c", res[i]);
    }
  }
  return 0;
}
