using System;

public class Program

{

    public static void Main()

    {

        //Console.WriteLine(MyVersion(5));

        Console.WriteLine(Viktorija(5));

    }

    public static int MyVersion(int n) {

        if(n == 1)

            return 0;

        return n*n-1+MyVersion(n-1);

    }

    public static int Viktorija(int n) {

        if(n==1) return 1;

        return 4*(n-1) + Viktorija(n-1);

    }

}