#include <bits/stdc++.h>

using namespace std;

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

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