#include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<bitset>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<deque>
#include<list>
#include<iomanip>
#include<cmath>
#include<cstring>
#include<functional>
#include<cstdio>
#include<cstdlib>
#include<unordered_map>
#include<unordered_set>
using namespace std;

#define repr(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep(i, n) repr(i, 0, n)
#define INF 2e9
#define MOD 1000000007
//#define MOD 998244353
#define LINF (long long)4e18
#define jck 3.141592

const double EPS = 1e-10;

using ll = long long;
using Pi = pair<int,int>;
using Pl = pair<ll,ll>;



int main(){
    int A,B; cin >> A >> B;
    if(A == B){
        cout << 1 << endl;
        return 0;
    }
    vector<int> a,b;
    while(A > 0){
        a.push_back(A%2);
        A /= 2;
    }
    while(a.size() < 40){
        a.push_back(0);
    }
    while(B > 0){
        b.push_back(B%2);
        B /= 2;
    }
    while(b.size() < 40){
        b.push_back(0);
    }
    ll ans = 1;
    rep(i,40){
        if(a[i] == 0 && b[i] == 1) ans *= 2;
        else if(a[i] == 1 && b[i] == 0) ans *= 0;
    }
    cout << ans/2 << endl;
}