# -*- coding: utf-8 -*-

D = int(input())

i = 0
while 4*(i+1)<=D:
    i += 1

answer = 0
if i == 0:
    print(answer)
else:
    d = D - 4*i
    ex_num = d // 2
    l1 = l2 = i
    if ex_num%2==0:
        l1 += ex_num//2
        l2 += ex_num//2
    else:
        l1 += ex_num//2
        l2 += ex_num//2 + 1
    print(l1*l2)