import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int b = sc.nextInt();
		sc.close();

		if ((a & b) != a) {
			System.out.println(0);
			return;
		}

		int c = b - a;
		int cnt = 0;
		for (int i = 0; i <= 32; i++) {
			if ((c >> i & 1) == 1) {
				cnt++;
			}
		}
		System.out.println(1L << (cnt - 1));
	}
}