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