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.
'''
# oj303
while True:
    try:
        x,y,z = map(int,input().split(" "))
        res = 1
        x = x % z
        while y != 0:
            if y & 1:
                res = (res * x) % z
            x = (x * x) % z
            y >>= 1
        print(res)
    except:
        break
'''
'''
import math
def is_prime(x):
    if x==0 or x==1:
        return 0
    if x==2:
        return 1
    for j in range(2, int(math.sqrt(x))+1):
        if x % j == 0:
            return 0
    return 1
n = int(input())
end = 1
for i in range(0,n):
    end = end*10
for i in range(int(end/10),end):
    t = i
    q = 0
    while t != 0:
        if q==1:
            break
        if is_prime(t) == 0:
            q = 1
        t = int(t/10)
    if q == 0:
        print(i)
'''
#OJ 776
'''
import math
for n in range(1, 26):
    cnt = 0
    for i in range(1,1000000000000000):
        if math.sqrt(i*(i+1)/2)-int(math.sqrt(i*(i+1)/2))<1e-100:
            cnt = cnt + 1
            if cnt==n:
                print("%d,%d" % (i, int(math.sqrt(i*(i+1)/2))))
                break
'''
from math import *
n = int(input())
if n % 2==0:
    print(int(pow(2,n/2)))
else:
    print("0")