N = int(input())
l = []
for i in range(N):
    k = N-i
    l.append(k)
for i in range(N):
    k = N-i
    l.append(k)
j = len(l)
l2 = []
for a in range (j-2):
    A = l[a]
    for b in range (j-2-a):
        ab = a+b+1
        B = l[ab]
        for c in range (j-2-a-b):
            abc = a+b+c+2
            C = l[abc]
            if A<B:
                if C<B:
                    if A != C:
                        l2.append([A,B,C])
            elif B<A:
                if B<C:
                    if A != C:
                        l2.append([A,B,C])
print(len(l2))