#include <iostream>

unsigned long int ans;
unsigned long int kaijo(unsigned long int);

using namespace std;

main()
{
	int N;
	unsigned long int tou;
	
	cin >> N;
	
	tou=0;
	for(int i=1;i<=N;i++){
	//	tou=tou*kaijo(2*(i-1)+1);
		tou=tou+i*(2*i-1);
	}
	cout << tou<< endl;
	
	return 0;
}

/*unsigned long int kaijo(unsigned long int a1)
{
	if(a1==1)
		return 1;
	else{
		ans=kaijo(a1-1);
		return ans + a1;
	}
}*/