#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
#define F first
#define S second
#define ll long long
int main()
{
  ll p,d,m,s;
    cin>>p>>d>>m>>s;
    ll ct=0;
    ll cut=p;
    if(p<m) cut=m;
    while(s>=cut)
    {
       s-=cut;ct++;
       if(cut-d>m)cut-=d;
       else cut=m;
        
       
    }
   cout<<ct;
	return 0;
}