#!/usr/bin/env python3
#coding:utf-8

import math
import string
from sys import stdin
# import numpy as np
# from matplotlib import pyplot as plt

	
def main():
	read=stdin.readline

	#edit here!
	d=int(read())
	x=d//4
	ans=x*(d//2-x)
	print(ans)
if __name__ == '__main__':
	main()