#include <bits/stdc++.h>

using namespace std;

using LL = long long;
const LL LINF = 1e18;



int main(){
    int A,B,C,D;cin >> A >> B >> C >> D;
    int ans = 0;
    for(int a = 0;a < 1000;a++){
        int w = a * C;
        if(a <= A && w <= B && a+w <= D){
            ans = a;
        }
    }
    cout<<ans<<endl;
    return 0;
}