#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
const long long inf = 0x3f3f3f3f;
const long long nax = 0;
int n;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie();
  cout.tie();
  cin >> n;
  vector<long long> f(65);
  f[1] = 0;
  f[2] = 2;
  for (int i = 3; i <= n; ++i) {
    f[i] = 2 * f[i - 2];
  }
  cout << f[n] << '\n';
}
