#include <bits/stdc++.h>

using namespace std;

#define SZ(x) (int)(x.size())

using ll = long long;
using ld = long double;
using P = pair<int, int>;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;
const double eps = 1e-10;
const int MOD = 1000000007;
const int INF = 1000000000;
const ll LINF = 1ll<<50;

template<typename T>
void printv(const vector<T>& s) {
  for(int i=0;i<(int)(s.size());++i) {
    cout << s[i];
    if(i == (int)(s.size())-1) cout << endl;
    else cout << " ";
  }
}

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(10);

  int a, b; cin >> a >> b;

  vvll dp(32, vll(2, 0));
  dp[0][0] = 1;

  for(int i=0;i<31;++i) {
    int ta = (a>>(30-i))&1, tb = (b>>(30-i))&1;
    if(tb == 0 || ta == 1) {
      dp[i+1][0] = dp[i][0];
      dp[i+1][1] = dp[i][1];
    } else if(ta == 0 && tb == 1) {
      dp[i+1][0] = 0;
      dp[i+1][1] = dp[i][0] + 2 * dp[i][1];
    } else {
      assert(false);
    }
  }

  cout << dp[31][0] + dp[31][1] << endl;
}