#include "bits/stdc++.h"
using namespace std;

int main(){
int a,b,c,d;
cin >> a >> b >>c >>d;
int ans =0;
for(int i=1+c;i<=d;i+=1+c){
    ans++;
}
if(ans>=a){
    cout << a <<endl;
}
else{
    cout << ans <<endl;
}
}