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

public class Solution {

    static int howManyGames(int p, int d, int m, int s) {
      int t;
       int ans=0;
     
        while(s-p>=0)
        {
            if(s-p>=0)
            {
                s=s-p;
                ans++;
                if(p-d>=m)
                p=p-d;
                else
                    p=m;
                
            }
        }
        return ans;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int p = in.nextInt();
        int d = in.nextInt();
        int m = in.nextInt();
        int s = in.nextInt();
        int answer = howManyGames(p, d, m, s);
        System.out.println(answer);
        in.close();
    }
}