#ifdef _DEBUG
#include "MyLib.h"
#else
#define main_B main
#include "bits/stdc++.h" 
#include <regex>
#define _USE_MATH_DEFINES
#include <math.h>
#define FOR(i,s,e) for (int i = int(s); i < int(e); ++i)
#define REP(i,e) FOR(i,0,e)
#define INF (INT_MAX/2)
#define EPS (1.0e-8)
#define LINF (LONG_MAX/2)
const int MGN = 8;
const int ARY_SZ_MAX = 10000000;
using namespace std;
using ll = long long; using ull = unsigned long long;
using vi = vector<int>; using vvi = vector<vi>; using vvvi = vector<vvi>;
using vb = vector<bool>; using vvb = vector<vb>; using vvvb = vector<vvb>;
using vl = vector<ll>; using vvl = vector<vl>;
using vd = vector<double>; using vs = vector<string>;
using pii = pair<int, int>; using pll = pair<ll, ll>;
// functions

#endif

ll cost(ll i, ll j) {
    return i * j + (j - i);
}

int main_B() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    
    int N; cin >> N;

    if (N==1) {
        cout << 0 << endl;
        return 0;
    }


    deque<int> dq;   
    
    if (N%2==0) {
        for (int i = N / 2; i >= 1;  i--) {
            if (i%2==0) {
                dq.push_back(i);
                dq.push_front(N+1-i);
            } else {
                dq.push_front(i);
                dq.push_back(N+1-i);
            }
        }
    } else {
        dq.push_back((N + 1) / 2);
        for (int i = N / 2; i >= 1;  i--) {
            if (i%2==1){
                dq.push_front(i);
                dq.push_back(N+1-i);
            } else {
                dq.push_back(i);
                dq.push_front(N+1-i);
            }
        }
    }

    ll ans = 0;
    int st = dq.front();
    int gl = dq.back();
    int i = dq.front(); dq.pop_front();
    while(!dq.empty()){
        int j = dq.front(); dq.pop_front();
        ans += cost(i, j);
        i = j;
    }
    ans += cost(gl, st);

    cout << ans << endl;

    return 0;
}