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;
const int dr[] = {+1, -1, +0, +0, +1, -1, -1, +1};
const int dc[] = {+0, +0, +1, -1, +1, -1, +1, -1};
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int foo;
  cin >> foo;
  cout << (foo & 1 ? 0 : (1LL << (foo / 2))) << '\n';
  return 0;
}
