#include <bits/stdc++.h>

using namespace std;
//1 3 5 7 9 11 13 15
long long int  sumOfGroup(long int k) {
    
  long  long int n=k*(k-1);
    //cout<<"After that"<<n;
    //cout<<"\nStart from "<<n+1;
    //long long  int a=1+n;
   // cout<<"\nStarting with "<<a;
    
    long long int s=k*(n+k);
  //  cout<<"\nSum "<<s;
        // cout<<s;
    return s;
    
    
    
    
     
    // Return the sum of the elements of the k'th group.
}

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