#define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include<queue>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>

//#include<bits/stdc++.h>



using namespace std;




int main() {
	

	
	int x;
	cin>>x;
	int a=x/4;
	int b=a;
	if(x%4>=2)b++;
	cout<<a*b<<endl;
	return 0;
}