#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define rep(i,s,e) for(int (i) = (s);(i) <= (e);(i)++)
#define all(x) x.begin(),x.end()

int main() {
  i64 a,b,c,d;
  cin >> a >> b >> c>> d;
  i64 ans = 0;
  for(int i = 0;i <= d;i++) {
    i64 m = i;
    if(m <= b) {
      ans = max(ans , min(a, m / c));
    }
  }
  cout << ans << endl;
}