#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 c=0;
    while(s>=p)
    {
        s-=p;
         if(s>=0)
        c++;
         // cout<<s<<" "<<p<<"\n";
        if(p-d>=m)
        {
            p-=d;
        }
        else
        {
            p=m;
        }
      
       
    }
    cout<<c<<"\n";
    
    return 0;
}