#include "bits/stdc++.h"
using namespace std;

typedef long long ll;

ll gcd(ll a, ll b) {
	if(b==0) return a;
	return gcd(b,a%b);
}

int main() {
	ll N;
	cin >> N;

	if(N%2==0) cout << gcd(N*N,(N-1)*(N/2)) << endl;
	else cout << gcd(N*N, N*(N/2)) << endl; 


}