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 powers[64];
void fill() {
  powers[0] = 1;
  for (int i = 1; i < 62; i++) {
    powers[i] = powers[i - 1] * 2;
  }
}
int n;
int main() {
  scanf("%d", &n);
  if (n % 2 == 1) {
    printf("0\n");
  } else {
    fill();
    printf("%lld\n", powers[n / 2]);
  }
  return 0;
}
