n = int(input())

a = 0
for i in range(1 << 2 * n):
    s = 0
    for j in range(2 * n):
        if i >> j & 1:
            s += 1
        else:
            s -= 1
        if s < 0:
            break
    if s == 0:
        a += 1

print(a)