#include <bits/stdc++.h>

using namespace std;

typedef pair<int,int> P;
typedef pair<int,pair<int,int>> PP;
typedef long long ll;

const double EPS = 1e-8;
const int INF = 1e9;
const int MOD = 1e9+7;

int dy[] = {0,1,0,-1};
int dx[] = {1,0,-1,0};

int main(void) {
	ll n;
	cin >> n;

	if(n == 1 || n == 3)cout << 1 << endl;
	else cout << fixed << setprecision(0) << pow(n/2,2) << endl;

	return 0;
}