import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws FileNotFoundException {
		long t = System.currentTimeMillis();
		new Main().run();
		System.err.println(System.currentTimeMillis() - t);
	}
	
	void run() {
		Scanner sc = new Scanner(System.in);
		int N=sc.nextInt();
		long X=sc.nextLong();
		long A=sc.nextLong();
		long B=sc.nextLong();
		long ans=Math.min((X+A-1)/A,((1L<<N-1)-X+B-1)/B);
		System.out.println(ans);
	}


	static void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}

}