#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

int main() {
	int A, B;
	cin >> A >> B;
	if (A == B) puts("1");
	else if ((A & B) < A) puts("0");
	else {
		ll ans = 1;
		REP(i, 31) {
			const int ai = A >> i & 1;
			const int bi = B >> i & 1;
			if (ai & bi) continue;
			if (!ai & !bi) continue;
			ans *= 2;
		}
		ans /= 2;
		cout << ans << endl;
	}
}