#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MOD 1000000007

int main() {
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	// your code goes here
	int m,p,d,s,count=0;
	
	cin>>m>>d>>p>>s;
	int sum=0;
	do
	{
		sum=sum+m;
		m-d>=p?m=m-d:m=p;
		count++;
	}while(sum<=s);
	
	cout<<count-1<<"\n";
	return 0;
}