#include <bits/stdc++.h> using namespace std; using ll = long long; using ull = unsigned long long; #define REP(i,n) for(long long i = 0; i < (n); i++) #define FOR(i, m, n) for(long long i = (m);i < (n); ++i) #define ALL(obj) (obj).begin(),(obj).end() #define SPEED cin.tie(0);ios::sync_with_stdio(false); template<class T> using V = vector<T>; template<class T, class U> using P = pair<T, U>; template<class T> using PQ = priority_queue<T>; template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>; constexpr long long MOD = (long long)1e9 + 7; constexpr long long MOD2 = 998244353; constexpr long long HIGHINF = (long long)1e18; constexpr long long LOWINF = (long long)1e15; constexpr long double PI = 3.1415926535897932384626433; template <class T> vector<T> multivector(size_t N,T init){return vector<T>(N,init);} template <class... T> auto multivector(size_t N,T... t){return vector<decltype(multivector(t...))>(N,multivector(t...));} template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}} template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;} template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;} template <class T>ostream &operator<<(ostream &o, const deque<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;} template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;} template <template <class tmp> class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} void print(void) {cout << endl;} template <class Head> void print(Head&& head) {cout << head;print();} template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);} template <class T> inline void chmax(T& a, const T b){a=max(a,b);} template <class T> inline void chmin(T& a, const T b){a=min(a,b);} void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;} void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;} void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;} int main() { ll N; cin >> N; corner(N==1,0); deque<ll> dq1,dq2; for(int i = 1; i <= N/2; ++i){ if(i%2) dq1.push_back(i); else dq1.push_back(N-(i-1)); } for(int i = 1; i <= N/2; ++i){ if(i%2) dq2.push_front(N-(i-1)); else dq2.push_front(i); } if(N%2) dq1.push_back(N/2+1); for(int i = 0; i < dq2.size(); ++i) dq1.push_back(dq2[i]); ll ans = 0; for(int i = 0; i < N; ++i) ans += dq1[i]*dq1[(i+1)%N]; cout << ans << endl; return 0; }