#include <bits/stdc++.h>
using namespace std;
#define rep(i, m, n) for (int i = m; i < n; ++i)
#define rem(i, m, n) for (int i = m; i >= n; --i)
typedef long long ll;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a = b; return 1; } return 0; }

int main() {
  int a, b, c, d;
  cin >> a >> b >> c >> d;
  int ans = 0;
  rep(i, 0, a + 1) {
    int n = i * c;
    if(i + n <= d && n <= b) ans = i;
    else break;
  }
  cout << ans << endl;
  return 0;
}