#include <bits/stdc++.h>
using namespace std;
#define int long long
#define REP(i,n) for(int i = 0;i < (int)(n);i++)
#define RREP(i,n) for(int i = (int)n-1;i >= 0;i--)
#define FOR(i,s,n) for(int i = s;i < (int)n;i++)
#define RFOR(i,s,n) for(int i = (int)n-1;i >= s;i--)
#define ALL(a) a.begin(),a.end()
#define IN(a, x, b) (a<=x && x<b)
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;}
constexpr long long INF = 1e18,MOD = 1000000007;

signed main(){
	int A,B;
	cin>>A>>B;
	if((A&B)!=A){
		cout<<0<<endl;
		return 0;
	}
	if(A==B){
		cout<<1<<endl;
		return 0;
	}
	int X = B ^ A;
	int cnt = 0;
	REP(i,60)if(X&(1ll<<i))cnt++;
	int ans = pow(2,cnt-1);
	cout<<ans<<endl;
}