#include <bits/stdc++.h>
using namespace std;
using ll = long long;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
ll mod = 1e9+7;


int main(){
    ll a,b; cin >> a >> b;
    int zo,oz,oo,zz;
    for(int i=0;i<31;i++){
        int x=0; x = a%2;
        int y=0; y = b%2;
      
        if(x==0 && y==1)
            zo++;
        if(x==1 && y==0){
            oz++;
            cout << 0 << endl;
            return 0;
        }
        if(x==1 && y==1)
            oo++;
        if(x==0 && y==0)
            zz++;
        a/=2; b/=2;
    }
    ll ans;
    if(zo==0){
        cout << 1 << endl;
    }else{
    ans = pow(2,(zo-1));
  cout << ans << endl;
    }
}