#include <bits/stdc++.h>
using namespace std;
const int NUM = 50;
const int mod = 1e9 + 7;
long long INF = 1e9 + 50;
pair<int, int> pinf = {INF, INF};
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(NULL);
  long long s, x, t;
  cin >> s >> x;
  t = s;
  long long bits[NUM];
  long long k = 0;
  for (int i = 0; i < NUM; i++) {
    bits[i] = (x >> i) % 2;
    if (bits[i] == 1) {
      k++;
      s -= ((long long)1 << i);
    }
  }
  if (s < 0) {
    cout << 0;
    return 0;
  }
  long long ans = (long long)1 << k;
  for (int i = 0; i < NUM; i++) {
    if (bits[i] == 0 && (i == 0 || bits[i - 1] == 1)) {
      if ((s >> i) % 2 == 1) {
        cout << 0;
        return 0;
      }
    }
    if (bits[i] == 1 && (i == 0 || bits[i - 1] == 1)) {
      if ((s >> i) % 2 == 1) {
        cout << 0;
        return 0;
      }
    }
  }
  if (t == x) ans -= 2;
  cout << ans;
  return 0;
}
