import java.util.Scanner;

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