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


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