#include <bits/stdc++.h>
using namespace std::literals::string_literals;
using i64 = std::int_fast64_t;
using std::cout;
using std::cerr;
using std::endl;
using std::cin;

template<typename T>
std::vector<T> make_v(size_t a){return std::vector<T>(a);}

template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts){
  return std::vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}

int main() {
	int a, b; scanf("%d%d", &a, &b);
	if(a == b) {
		printf("1\n");
		return 0;
	}
	
	i64 ans = 1;
	for(int i = 0; i < 32; i++) {
		if(a >> i & 1) ans *= 1;
		else ans *= (1 + (b >> i & 1));

		if((a >> i & 1) and !(b >> i & 1)) ans = 0;
	}
	ans >>= 1;
	printf("%lld\n", ans);
	return 0;
}