#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;

#define ll long long
#define INF (1 << 30)
#define INFLL (1LL << 60)

int main() {
	int n,a;
	cin >> n;
	a = n / 2;
	if(n < 4) cout << 0 << endl;
	else if(a % 2 == 1){
		cout << (a / 2) * (a / 2 + 1) << endl;
	}else{
		cout << (a / 2) * (a / 2) << endl;
	}
	return 0;
}