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 sum=0;
        int games=0;
        while(p<=s)
        {
            if(p-d>=m)
            {
                s=s-p;
                p=p-d;
                games++;
            }
            else if(p-d<m)
            {
                s=s-p;
                p=m;
                games++;
            }
        }
        return games;
    }
    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();
    }
}