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;
int in() {
  int ret;
  cin >> ret;
  return ret;
}
const int N = 2e5 + 10, INF = 1e9 + 7;
int n;
long long ans;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  if (n % 2)
    ans = 0;
  else
    ans = 1;
  for (int i = 0; i < (n / 2); i++) ans *= 2;
  cout << ans << '\n';
  return 0;
}
