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.
# ///==========Libraries, Constants and Functions=============///
#mkraghav
import sys

inf = float("inf")
mod = 1000000007


def get_array(): return list(map(int, sys.stdin.readline().split()))


def get_ints(): return map(int, sys.stdin.readline().split())


def input(): return sys.stdin.readline()

def int1():return int(input())

import string

import math

from itertools import combinations
# ///==========MAIN=============///


def main():
    n=int1()
    if n==1:
        print(0)
    else:
        if n%2==0:
            print(pow(2,n//2))
        else:
            print(0)








if __name__ == "__main__":
    main()
