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;
long long int tmp;
void MAIN() {
  int t = 1;
  while (t--) {
    int n;
    cin >> n;
    long long int po[61];
    po[0] = 1;
    for (int i = 1; i < 61; i++) {
      po[i] = 2 * po[i - 1];
    }
    if (n & 1) {
      cout << 0;
      return;
    } else {
      cout << po[n / 2];
    }
  }
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  MAIN();
}
