#include <iostream>

using namespace std;

int main(){
    int a, b;
    cin >> a >> b;
    if(a != a & b){
        cout << 0 << "\n";
        return 0;
    }
    if(a == b){
        cout << 1 << "\n";
        return 0;
    }
    int c = a ^ b;
    int ans = 1;
    while(c){
        if(c % 2){
            ans *= 2;
        }
        c /= 2;
    }
    cout << ans / 2 << "\n";
}