N = int(input())
ans = 0

for i in range(2 ** (2*N)):
    left = 0
    right = 0
    bit = bin(i)
    flg = 0
    for j in range(N * 2):
        if (i >> j) & 1:
            left += 1
        else:
            right += 1
        if left < right:
            flg = 1
            break
    if flg == 0 and left == right:
        ans += 1

print(ans)