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


int main() {
    long p,d,m,s;
    cin>>p>>d>>m>>s;
    long curr = p;   
    long long count =0;
    while(s>0){
        //cout<<s<<" ";
        if(curr<=s)
            count++;
        s=s-curr;
       curr = curr-d;
       if(curr<=m)
       {curr=m;
        d=0;
       }
    }
    cout<<count;
    return 0;
}