#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, p;
  cin >> n;
  if (n == 1)
    cout << "0";
  else if (n % 2 == 0) {
    p = pow(2, (n / 2));
    cout << p;
  } else if (n % 2 == 1)
    cout << "0";
  return 0;
}
