#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    if (n == 1) {
        cout << 0 << endl;
        return 0;
    } else if (n == 2) {
        cout << 4 << endl;
        return 0;
    }
    vector<int> p(n+1);
    p.at(0) = 2;
    p.at(n) = 2;
    p.at(1) = n;
    p.at(2) = 1;
    for (int i = 3; i < n; i++) {
        p.at(i) = i % 2 == 1 ? n - i / 2 : i / 2 + 1;
    }
    long s = 0;
    for (int i = 0; i < n; i++) {
        s += p.at(i) * p.at(i + 1);
    }
    cout << s << endl;
}