#include <bits/stdc++.h>
using namespace std;
int main() {
  int long long n;
  int long long ans;
  cin >> n;
  vector<int long long> dp(n + 1, 0);
  dp[0] = 0;
  dp[1] = 0;
  dp[2] = 2;
  for (int long long i = 4; i <= n; i += 2) {
    dp[i] = 2 * dp[i - 2];
  }
  cout << dp[n] << endl;
  return 0;
}
