#include <bits/stdc++.h>
using namespace std;
const int N = 1e4 + 7;
int dp[N];
int main(void) {
  int n;
  cin >> n;
  int dp[n + 1];
  dp[1] = 0, dp[2] = 2;
  for (int i = 3; i <= n; i++) {
    dp[i] = dp[i - 2] * 2;
  }
  cout << dp[n] << endl;
  return 0;
}
