#include<bits/stdc++.h>
using namespace std;
long long p,m,d,s,ans;
int main(){
	cin>>p>>d>>m>>s;
	while(s>=0){
		s-=p;
		if(p>d+m)p-=d;
		else p=m;
		ans++;
	}
	
	cout<<ans-1;
	return 0;
}