#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main() {
    int A, B;
    cin >> A >> B;
    bitset<32> a(A), b(B);
    int ans = 1;
    for (int k = 0; k < 32; k++) {
        if (a[k] && !b[k]) {
            cout << 0 << endl;
            return 0;
        }
        if (!a[k] && b[k]) {
            ans <<= 1;
        }
    }
    if (A != B) ans >>= 1;
    cout << ans << endl;
}