#include <bits/stdc++.h>
using namespace std;
using lint = long long;
template<class T = int> using V = vector<T>;
template<class T = int> using VV = V< V<T> >;

int main() {
  cin.tie(nullptr); ios::sync_with_stdio(false);
  lint n; cin >> n;
  if (n == 1) return cout << 0 << '\n', 0;
  if (n & 1) {
    cout << (n * n * n + 3 * n * n + 5 * n - 3) / 6 << '\n';
  } else {
    cout << (n * n * n + 3 * n * n + 5 * n - 6) / 6 << '\n';
  }
}