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) {
        // Return the number of games you can buy
        int buy =0 ;
        int price= p;
        int sum =0;
        while(price>m){
            sum+=price;
            if(sum<=s){
                buy++;
                price-=d;        
            }else{
                break;
            }
        }
        
        while(sum<=s){
            sum+=m;
            if(sum<=s){
                buy++;
            }
            else break;
        }
        return buy;
        
    }

    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();
    }
}