func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 2e5 + 10, inf = 1e9 + 10, P = 53, MOD = 1e9 + 7;   vector<int> a, b;   int main() {     ios_base::sync_with_stdio(false);     long long n, x, t = 0;     long long ans = 1;     cin >> n >> x;     for (int i = 0; i < 42; i++)       if ((1ll << i) & x) {         ans *= 2;         n -= (1ll << i);         t++;       }     if (n < 0 || (n == 0 && t == 1)) {       cout << 0;       return 0;     }     if (n == 0) {       cout << ans - 2;       return 0;     }     for (int i = 0; i < 42; i++)       if (!((1ll << i) & x))         if ((1ll << (i + 1)) & n) n -= (1ll << (i + 1));     if (n == 0)       cout << ans;     else       cout << 0;     return 0;   }   