import java.util.Scanner;

public class No598 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long N = sc.nextInt();
		long X = sc.nextInt();
		long A = sc.nextInt();
		long B = sc.nextInt();
		long MAX =(long)Math.pow(2, N-1);
		
		System.out.println((long)Math.min(Math.ceil((double)X/A),Math.ceil((double)(MAX-X)/B)));
	}
}