#include <bits/stdc++.h>

using namespace std;

using int64 = long long;

int main() {
  int X, Y;
  cin >> X >> Y;
  vector< vector< int64 > > dp(50, vector< int64 >(2, -1));
  function< int64(int, bool) > rec = [&](int idx, bool low) -> int64 {
    if(idx == -1) return 1;
    if(~dp[idx][low]) return dp[idx][low];
    int u = (X >> idx) & 1;
    int v = (Y >> idx) & 1;
    int64 ret = 0;
    for(int j = 0; j < 2; j++) {
      for(int k = 0; k < 2; k++) {
        int s = j & k;
        int t = j | k;
        if(u == s && v == t) {
          if(!low && j > k) continue;
          ret += rec(idx - 1, low | (j < k));
        }
      }
    }
    return dp[idx][low] = ret;
  };
  cout << rec(30, false) << endl;
}