#include using namespace std; typedef long long signed int LL; typedef long long unsigned int LU; #define incID(i, l, r) for(LL i = (l) ; i < (r); ++i) #define incII(i, l, r) for(LL i = (l) ; i <= (r); ++i) #define decID(i, l, r) for(LL i = (r) - 1; i >= (l); --i) #define decII(i, l, r) for(LL i = (r) ; i >= (l); --i) #define inc(i, n) incID(i, 0, n) #define inc1(i, n) incII(i, 1, n) #define dec(i, n) decID(i, 0, n) #define dec1(i, n) decII(i, 1, n) #define inID(v, l, r) ((l) <= (v) && (v) < (r)) #define inII(v, l, r) ((l) <= (v) && (v) <= (r)) #define PB push_back #define EB emplace_back #define MP make_pair #define FI first #define SE second #define ALL(v) v.begin(), v.end() #define RALL(v) v.rbegin(), v.rend() template bool setmin (T & a, T b) { if(b < a) { a = b; return true; } else { return false; } } template bool setmax (T & a, T b) { if(b > a) { a = b; return true; } else { return false; } } template bool setmineq(T & a, T b) { if(b <= a) { a = b; return true; } else { return false; } } template bool setmaxeq(T & a, T b) { if(b >= a) { a = b; return true; } else { return false; } } LL mo(LL a, LL b) { assert(b > 0); a %= b; if(a < 0) { a += b; } return a; } LL fl(LL a, LL b) { assert(b > 0); return (a > 0 ? a / b : (a - b + 1) / b); } LL ce(LL a, LL b) { assert(b > 0); return (a < 0 ? a / b : (a + b - 1) / b); } template T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); } template T lcm(T a, T b) { return a / gcd(a, b) * b; } #define bit(b, i) (((b) >> (i)) & 1) #define BC __builtin_popcountll #define SC static_cast #define SI(v) SC(v.size()) #define SL(v) SC(v.size()) #define RF(e, v) for(auto & e: v) #define ef else if #define UR assert(false) // ---- ---- LL n, ans; int main() { cin >> n; deque x, y; inc(i, n) { if(i % 4 == 0) { x.push_back(i / 4 * 2 + 1); } if(i % 4 == 1) { y.push_front(n - (i / 4 * 2)); } if(i % 4 == 2) { x.push_back(n - (i / 4 * 2 + 1)); } if(i % 4 == 3) { y.push_front(i / 4 * 2 + 2); } } RF(e, y) { x.PB(e); } x.PB(x[0]); inc(i, n) { ans += x[i] * x[i + 1]; } if(n == 1) { ans = 0; } cout << ans << endl; return 0; }