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.
def solve(n):
    dp = [0] * (n+1)
    dp[0] = 0
    dp[1] = 0




    for i in range(2,n+1):
        if i == 2:
            dp[i] = 2
            continue

        if i % 2 != 0 :
            dp[i] = 0
        else:
            dp[i] = dp[i-2] * 2

    print(dp[n])


if __name__ == '__main__':
    n = int(input())

    solve(n)