#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

ll gcd(ll n, ll m) {
	if (n < m) {
		ll c = n;
		n = m;
		m = c;
	}
	if (m == 0) {
		return n;
	}
	if (n%m == 0) {
		return m;
	}
	else {
		return gcd(m, n%m);
	}
}

int main() {
	ll n;
	cin >> n;
	ll sum;
	if (n % 2 == 0) {
		sum = (n - 1)*(n / 2);
	}
	else {
		sum = (n / 2)*n;
	}
	cout << gcd(n, sum) << endl;

	return 0;
}