#include <bits/stdc++.h>
using namespace std;
int main(int argc, char const *argv[])
{
	long long int k;
	cin>>k;
	long long int sum_array[1000001]={0};
	int end_index=(k*(k+1))/2;
	long long int start_index=end_index-k;
	sum_array[1]=1;
	for (int i =2;i<=1000000; ++i)
	{
		long long int odd_num=2*i-1; 
		sum_array[i]=odd_num+sum_array[i-1];
	}
	// for (int i = 1; i<=100 ; ++i)
	// {
	// 	cout<<sum_array[i]<<" ";
	// }
	// cout<<endl;
	// cout<<sum_array[end_index]<<" "<<sum_array[start_index]<<endl;
	cout<<sum_array[end_index]-sum_array[start_index]<<endl;	
	return 0;
}