#include <bits/stdc++.h>
#define rep(i,n) for(int i=(0);i<(n);i++)

using namespace std;

typedef long long ll;

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);

	int a, b;
	cin >> a >> b;

	if(a > b){
		cout << 0 << "\n";
		return 0;
	}

	int ans = 1;
	bool dif = false;
	for(int i = 30; i >= 0; i--){
		
		int m = 1 << i;
		// cerr << i << "," << (a & m) << "," << (b & m) << endl;

		if((a & m) > (b & m)){
			cout << 0 << "\n";
			return 0;
		}else if((a & m) < (b & m)){
			if(dif){
				ans *= 2;
			}else{
				dif = true;
			}
		}
	}

	cout << ans << endl;
}