#include<cstdio>
#include<iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>
#include<limits>

#define all(x) (x).begin(),(x).end()
#define rall(x) (x).rbegin(),(x).rend()

using namespace std;
typedef long long ll;
typedef pair<int, int> pi;
typedef pair<ll, ll> pl;
typedef pair<ll, string> pls;

int main()
{
	int D;
	cin >> D;
	
	ll ans = 0;
	if (D / 4 == 0) {
		ans = 0;
	}
	else {
		if (D % 4 == 0) {
			ans = (D / 4)*(D / 4);
		}
		else {
			int add = 0;
			if (D % 4 >= 2)add = 1;
			ans = (D / 4)*(D / 4 + add);
		}
	}
	cout << ans << endl;
	return 0;
}