#include<bits/stdc++.h>
using namespace std;
#define ll long long int
#define MOD 1000000007
#define M(x) (x%MOD + MOD)%MOD
#define _pb push_back
#define _mp make_pair
#define ff first
#define ss second
#define s(x) scanf("%lld",&x)

ll mul(ll x,ll y)
{ ll ans=1;

  while(y>0)
  { if(y&1)
	ans=(ans*x)%MOD;
	y/=2;
	x=(x*x)%MOD;
  }
  
  return ans;
};

/**********************************************/

int main()
{
 	ll k,a,d,ans;
 	s(k);
 	
 	a = k*(k-1)+1;
 	d = 2;
 	
 	ans = (k*(a + (k-1)));
 	cout<<ans;
 	return 0;
}