//There was and will always be only one Chester
//RIP legend
#include<bits/stdc++.h>
#define Nilesh ios_base::sync_with_stdio(false)
using namespace std;
int main()
{
        int p,d,m,s;
        cin>>p>>d>>m>>s;
        int cnt=0;
        while(s>=0)
        {
            if(p>=m)
            {
                s-=p;
                p-=d;
            }
            else
                s-=m;
            cnt++;
        }
        cout<<cnt-1;
}