#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 cnt=0,amt=0;
    if(p>s){
        cout<<cnt;
        return 0;
    }
    else{
        while(s>0){
            
            if(p<=m){
                p=m;
                s=s-p;
               
            }
            else{
                s=s-p;
            p=p-d;
            }
            if(s>=0){
                cnt++;
            }
        }
    }
    cout<<cnt;
    return 0;
}