#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<pair<int, int>, int> PP;
const ll INF = 1LL << 60;
const ll MOD = 1000000007;

int GCD(int a, int b) { return b ? GCD(b, a%b) : a; }
//------------------------------------------------------------------------------------------------------------------------------

int main(void) { 
    ll A, B;
    int ans = 1;
    cin >> A >> B;
    bool flag = false;
    for (int i = 60; i >= 0; i--) {
        ll d = 1LL << i;
        if ((A & d) && !(B & d)) {
            ans = 0; 
        }
        else if(!(A & d) && (B & d)){
            if (!flag) flag = true;
            else ans *= 2;
        }
    }
    cout << ans << endl;
}