#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <vector>
using namespace std;
typedef pair<int, int> pii;
#define REP(i,x) for(int i=0;i<(int)(x);i++)

int main(){
	int n;
	cin >> n;
	cout << ( n%4<2 ? (n/4)*(n/4) : (n/4)*(n/4 + 1) ) << endl;
	return 0;
}