#include <bits/stdc++.h>
using namespace std;

typedef vector<int> vi;
typedef pair<int, int> ii;
typedef long long ll;
typedef pair<long long, long long> l4;
typedef vector<long long> vll;
typedef double db;
typedef vector<double> vdb;
typedef pair<double, double> dd;
typedef set<int> si;
typedef set<long long> sll;
#define fi first
#define se second
#define matrix(a) vector< vector<a> >
#define sz(a) int((a).size()) 
#define lop(i,a,b) for (int i=a; i<=b; i++)
#define rlop(i,a,b) for (int i=b; i>=a; i--)
#define all(s) (s).begin(),(s).end()
#define pb push_back
#define enter cout<<'\n'
#define lb(i,v) int(lower_bound(all(v),i)-v.begin())
#define ub(i,v) int(upper_bound(all(v),i)-v.begin())


int main() {
    ll k;
    cin >> k;
    cout << (k*(k-1)+k*(k+1))*k/2 << endl;
    return 0;
}