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 main() {
  int n;
  cin >> n;
  int64_t res = 1;
  if (n % 2 == 1) {
    res = 0;
  } else {
    for (int i = 0; i < n / 2; ++i) {
      res *= 2;
    }
  }
  cout << res << "\n";
  return 0;
}
