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.
import math

class Input():
	def readInt(self):
		return int(input())

	def readIntArray(self):
		return [int(x) for x in input().split(" ")]

	def readString(self):
		return input()

	def readStringArray(self):
		return input().split(" ")

	def readFloat(self):
		return float(input())

	def readFloatArray(self):
		return [float(x) for x in input().split(" ")]

def count(n, dp):
	if n in dp:
		return dp[n]
	if n == 1:
		dp[n] = 0
		return dp[n]
	if n == 2:
		dp[n] = 2
		return dp[n]
	dp[n] = count(n-2, dp) * 2
	return dp[n]

def main():
	inp = Input()
	n = inp.readInt()
	dp = {}
	ans = count(n, dp)
	print(ans)


if __name__ == "__main__":
   main()
  			 	 		  	   	    		  	 				