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;
ostream& operator<<(ostream& os, const vector<long long>& a) {
  for (int i = 0; i < a.size(); i++) os << a[i] << " ";
  return os;
}
int main() {
  long long n;
  cin >> n;
  vector<long long> p(n + 1);
  p[0] = 1;
  for (int i = 1; i <= n; i++) p[i] = p[i - 1] * 2ll;
  if (n % 2 != 0)
    cout << 0 << endl;
  else
    cout << p[n / 2] << endl;
  return 0;
}
