#include <iostream>

using lint = long long;

void solve() {
    lint n;
    std::cin >> n;

    if (n == 1) {
        std::cout << 0 << "\n";
        return;
    }

    if (n % 2 == 0) {
        std::cout << (n * n * n + n * n * 3 + n * 5 - 6) / 6 << "\n";
    } else {
        std::cout << (n * n * n + n * n * 3 + n * 5 - 3) / 6 << "\n";
    }
}

int main() {
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    solve();

    return 0;
}