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 count = 0;
        int less = 0;
        
        while(s >= (m) && s >= (p - less)){
            count++;
            if((p - less) > m){
                s = s - (p - less);    
            }
            else{
                s = s - m;
            }
            if((p - less) > m)
                less += d;
        }
        return count;
    }

    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();
    }
}