/* -*- coding: utf-8 -*-
 *
 * 939.cc:  No.939 and or - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int a, b;
  scanf("%d%d", &a, &b);

  if ((a & b) != a) {
    puts("0");
    return 0;
  }

  int c = a ^ b;
  int n = 0;
  for (int bi = 1 << 30; bi > 0; bi >>= 1)
    if (c & bi) n++;
  //printf("n=%d\n", n);

  printf("%d\n", (n == 0) ? 1 : 1 << (n - 1));
  return 0;
}