#include <bits/stdc++.h>

using namespace std;

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

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