n = int(input())
y = []
for i in range(1, n // 2 + 1):
    x = (n - (i * 2)) * (n - (i * 2)) * i
    y.append(x)
print(max(y))
/**************************************************************
	Problem: 1350
	User: linmiaoling
	Language: Python
	Result: Accepted
	Time:91 ms
	Memory:34244 kb
****************************************************************/