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);