#pragma once

#include <bits/stdc++.h>

#define M_PI       3.14159265358979323846   // pi

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> VI;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> t3;
typedef tuple<ll, ll, char, ll> t4;

#define rep(a,n) for(int a = 0;a < n;a++)
#define repi(a,b,n) for(int a = b;a < n;a++)

const ll mod = 1000000007;

bool Compare(t4& left, t4& right) {
	ll a, b, d, e, f,h;
	char c, g;
	tie(a, b, c, d) = left;
	tie(e, f, g, h) = right;
	if (a == e) {
		return d < h;
	}
	return a < e;
}

int main(void)
{
	ll a, b;
	cin >> a >> b;
	bool aBits[32];
	bool bBits[32];
	rep(i, 32) {
		aBits[i] = a & (1 << i);
		bBits[i] = b & (1 << i);
		if (aBits[i] && !bBits[i])
		{
			cout << 0 << endl;
			return 0;
		}
	}
	int d = 0;
	rep(i, 32) {
		if (bBits[i] && !aBits[i])
		{
			d++;
		}
	}
	cout << (1LL << max(0, (d - 1))) << endl;
	return 0;
}