N = int(input())

from copy import copy
from itertools import accumulate

ans = 0
for S in range(1<<2*N):
    b = format(S, 'b').zfill(2*N)
    b = list(map(int, list(b)))
    b = list(map(lambda x: x if x == 1 else -1, b))
    ac = list(accumulate(b))

    if all(x >= 0 for x in ac) and ac[-1] == 0:
        ans += 1

print(ans)