#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

int main() {
	int N;
	cin >> N;
	if (N == 1) { puts("0"); return 0; }
	
	vector<int> A(N);
	for (int i = 0, l = 0, r = 1; i < N; i += 4) {
		const int c = i >> 1;
		A[l] = 1 + c;
		if (i + 1 < N) A[r] = N - c;
		l = (l + N - 1) % N;
		r = (r + 1) % N;
		swap(l, r);
		
		if (i + 2 < N) A[l] = 2 + c;
		if (i + 3 < N) A[r] = N - 1 - c;
		l = (l + 1) % N;
		r = (r + N - 1) % N;
		swap(l, r);
	}
	
	ll ans = 0;
	REP(i, N) ans += (ll)A[i] * A[(i + 1) % N];
	cout << ans << endl;
}