#include <iostream>

void solve() {
    int x, y;
    std::cin >> x >> y;

    if ((x & y) != x) {
        std::cout << 0 << std::endl;
        return;
    }

    int c = __builtin_popcount(x ^ y);
    std::cout << (c == 0 ? 1 : 1 << (c - 1)) << std::endl;
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}