n = int(input())
a = [0, 1]
for i in range(2, n + 1):
    if (i % 2 == 0):
        a += [i * sum([a[j] for j in range(1, i) if j % 2 != 0])]
    else:
        a += [i * sum([a[j] for j in range(1, i) if j % 2 == 0])]
print(a[-1])