import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        if (a == b) {
            System.out.println(1);
            return;
        } else if ((a & b) != a) {
            System.out.println(0);
            return;
        }
        int c = b - a;
        int count = 0;
        while (c > 0) {
            count += c % 2;
            c /= 2;
        }
        System.out.println(1 << (count - 1));
    }
}