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]);
        if ((a & b) != a) {
            System.out.println(0);
            return;
        }
        int count = 0;
        int c = b - a;
        while (c > 0) {
            count += c % 2;
            c /= 2;
        }
        System.out.println((long)(Math.pow(2, count - 1)));
    }
}