#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios::sync_with_stdio(false); cin.tie(0);
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  int ans = 0;
  for (int i = 0; i < 1000; i++) {
    b -= c;
    d -= c;
    if (b < 0 || d < 0) break;
    ans++, a--;
    if (a == 0) break;
  }
  cout << ans << endl;
  return 0;
}