#include <bits/stdc++.h>

using namespace std;

long long int sumOfGroup(long long int k) {
    long long int noOfOdds = k * (k + 1) / 2;
    long long int TotalSum = noOfOdds * noOfOdds;
    long long int n_low = (k - 1) * (k) / 2;
    long long int TotalSum_1 = n_low * n_low;
    return (TotalSum - TotalSum_1);
}

int main() {
    long long int k;
    cin >> k;
    long long int answer = sumOfGroup(k);
    cout << answer << endl;
    return 0;
}