#include <bits/stdc++.h>

using namespace std;

long sumOfGroup(long k) {
    long istart = k * (k - 1) / 2;
    long iend = k * (k + 1) / 2;
    long start = 1L + istart * 2;
    long count = iend - istart;
    return start * count + count * (count - 1);
}

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