import java.util.*;
import java.io.*;

public class Main {
    public static void main(String[] args) throws Exception {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] line = br.readLine().split(" ", 2);
        int a = Integer.parseInt(line[0]);
        int b = Integer.parseInt(line[1]);
        int count = 0;
        while (a > 0 && b > 0) {
            if (a % 2 == 0 && b % 2 == 1) {
                count++;
            } else if (a % 2 == 1 && b % 2 == 0) {
                System.out.println(0);
                return;
            }
            a /= 2;
            b /= 2;
        }
        System.out.println((long)(Math.pow(2, count - 1)));
    }
}