#include <bits/stdc++.h>
using namespace std;

int main() {
  int A, B;
  cin >> A >> B;
  int ans = 0;
  if ((A & B) != A) ans = 0;
  else if (A == B) ans = 1;
  else ans = 1 << (__builtin_popcount(B - A) - 1);
  cout << ans << "\n";
}