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 in = new Scanner(System.in);
		int p = in.nextInt();
		int d = in.nextInt();
		int m = in.nextInt();
		int s = in.nextInt();
		int day = 0;
		int update = 0;
		boolean flag = true;
		while(s>0)
		{
			if(flag)
			{
				if(p - day*d > m)
					update = p - day*d;
				else
				{
					update = m;
					flag = false;
				}
				
			}
			s  = s - update;
			day++;
		}
        if(s == 0)
        	System.out.println(day);
        else
            System.out.println(day-1);
           
		in.close();
	}
}