import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {


    public static void main(String[] args) {
        Scanner st = new Scanner(System.in);
        int price = st.nextInt();
        int d = st.nextInt();
        int m = st.nextInt();
        int s = st.nextInt();
        boolean i=true;
       int count=0;
        while(i)
        {
            s=s-price;
            
                if(s<0)
                {break;}
               count++;
            price=price-d;
            if(price<=m)
            {
                price=m;
                break;
            }
            }
        while(s>0){
            s=s-price;
            if(s>=0){
            count++;}
        }
        
        System.out.println(count);
    }
}