You have a given integer n. Find the number of ways to fill all 3 × n tiles with the shape described in the picture below. Upon filling, no empty spaces are allowed. Shapes cannot overlap.

<image> This picture describes when n = 4. The left one is the shape and the right one is 3 × n tiles. 

Input

The only line contains one integer n (1 ≤ n ≤ 60) — the length.

Output

Print the number of ways to fill.

Examples

Input


4


Output


4

Input


1


Output


0

Note

In the first example, there are 4 possible cases of filling.

In the second example, you cannot fill the shapes in 3 × 1 tiles.
#include <bits/stdc++.h>
using namespace std;
void OFFLINE() {}
unsigned long long Pow(unsigned long long expo) {
  unsigned long long result = 1ull;
  unsigned long long base = 2;
  while (expo > 0) {
    if (expo % 2 == 1) result *= base;
    base = base * base;
    expo /= 2;
  }
  return result;
}
int main() {
  std::ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  unsigned long long n;
  cin >> n;
  unsigned long long ans = 0;
  if (n % 2 == 0) ans = Pow(n / 2);
  cout << ans << "\n";
  return 0;
}
