#include <bits/stdc++.h>
int main() {
  int n;
  scanf("%d", &n);
  if (n <= 2) {
    if (n == 1) printf("0");
    if (n == 2) printf("2");
  } else {
    long long sum = 1;
    for (int i = 0; i < n / 2; i++) sum *= 2;
    if (n % 2 == 0)
      printf("%lld", sum);
    else
      printf("0");
  }
}
