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