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 sys
import math
from collections import defaultdict as ddict
from collections import deque
import heapq
from queue import Queue

fast_inp = lambda: sys.stdin.readline().split('\n')[0]
read_list = lambda: fast_inp().split(' ')
read_listi = lambda: list(map(int, fast_inp().split(' ')))
read_listf = lambda: list(map(float, fast_inp().split(' ')))
read_int = lambda: int(fast_inp())
read_float = lambda: float(fast_inp())
read = lambda: fast_inp()
DEBUG = False


def debug(**kwargs):
    if not DEBUG:
        return
    print('*' * 20)
    for k, v in kwargs.items():
        print(f'\t{k}:{v}\t')
    print('*' * 20)



def solve() -> None:
    n = read_int()
    if n & 1:
        print(0)
    else:
        print(pow(2, n//2))


t = 1
for _ in range(t):
    solve()