/**
 *  author:   TakeruOkuyama
 *  created:  2020-04-09 14:53:46
**/
#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;

int main(){
    int A, B, C, D;
    cin >> A >> B >> C >> D;
    int ans = 0;
    for(int i = 1; i <= A; i++){
        if(i * C <= B && i + i * C < D){
            ans = i;
        }
    }
    cout << ans << endl;
return 0;}

/**
**/