#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pii pair<int, int>
#define eb emplace_back
#define all(v) v.begin(), v.end()
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep3(i, l, n) for (int i = l; i < (n); ++i)
#define sz(v) (int)v.size()
#define inf (int)(1e9+7)
#define INF (ll)(1e18)
#define abs(x) (x >= 0 ? x : -(x))
#define ceil(a, b) a / b + !!(a % b)
template<typename T1, typename T2> inline bool chmin(T1 &a, T2 b) { if (a > b) { a = b; return 1; } return 0; }
template<typename T1, typename T2> inline bool chmax(T1 &a, T2 b) { if (a < b) { a = b; return 1; } return 0; }
template<typename T> T gcd(T a, T b) { if (b == 0) return a; return gcd(b, a % b); }



int main() {
    int a, b;
    cin >> a >> b;
    
    ll ans = 1;
    while (a && b) {
        if (a % 2 == 1 && b % 2 == 0) { cout << 0 << endl; return 0; }
        
        if (a % 2 == 0 && b % 2 == 1) ans *= 2;
        a /= 2; b /= 2;
    }
    cout << ans / 2 << endl;
}