#include <bits/stdc++.h>

using namespace std;

long long sumOfGroup(long long k) {
    // Return the sum of the elements of the k'th group.
    return 1ll*k*((long long)1+(1ll*(k+1)*(k-1)));
}

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