#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
int main(void){
    int a,b,c,d,ans;
    cin>>a>>b>>c>>d;
    ans=b/c;
    if(ans<=a && (ans+ans*c)<=d){
        cout<<ans<<endl;
    }else if((a+a*c)<=d){
        cout<<a<<endl;
    }else{
        cout<<d/(c+1)<<endl;
    }
    
}