#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int p,d,m,s;
    cin>>p>>d>>m>>s;
    int ans=0;
    if(s>=p)
    {
        ans++;
        s-=p;
        int cp=p-d;
        while(cp>m)
        {
            if(s>=cp)
            {
                ans++;
                s-=cp;
                cp=cp-d;
            }
            else
                break;
        }
        while(s>=m && cp<=m)
        {
            ans++;
            s-=m;
        }
    }
    cout<<ans<<endl;
    return 0;
}