1182_A. Filling Shapes
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.
```python
import sys
from random import choice,randint
inp=sys.stdin.readline
out=sys.stdout.write
flsh=sys.stdout.flush
 
sys.setrecursionlimit(10**9)
inf = 10**20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1,0),(0,1),(1,0),(0,-1)]
ddn = [(-1,0),(-1,1),(0,1),(1,1),(1,0),(1,-1),(0,-1),(-1,-1)]
 
def MI(): return map(int, inp().strip().split())
def LI(): return list(map(int, inp().strip().split()))
def LLI(): return [list(map(int, l.split())) for l in sys.stdin.readlines().strip()]
def LI_(): return [int(x)-1 for x in inp().strip().split()]
def LF(): return [float(x) for x in inp().strip().split()]
def LS(): return inp().strip().split()
def I(): return int(inp().strip())
def F(): return float(inp().strip())
def S(): return inp().strip()
def pf(s): return out(s+'\n')
def JA(a, sep): return sep.join(map(str, a))
def JAA(a, s, t): return s.join(t.join(map(str, b)) for b in a)

def main():
    n = I()
    # ans = (1-n%2)<<(n//2)
    # pf(str(ans))
    dp=[0]*(n+1)
    dp[0]=1
    for i in range(2,n+1):
        if i%2==0:
            dp[i]=(dp[i-2]<<1)
    pf(str(dp[n]))

if __name__ == "__main__":
    main()
```