using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Leap years are years where an extra, or intercalary,");

        Console.WriteLine("day is added to the end of the shortest month, February.");

        Console.WriteLine("The intercalary day, February 29, is commonly referred to as leap day.");

        Console.WriteLine("Leap years have 366 days instead of the usual 365 days and occur almost every four years.");

        Console.WriteLine();

        start:

        Console.WriteLine("Please enter a a year after 1582.");

        string input = Console.ReadLine();

        ulong n;

        if(ulong.TryParse(input, out n))

        {

            if(n>0)

            {

                Console.WriteLine();

            }

        }

        else

        {

            Console.Clear();

            goto start;

        }

        ulong year = ulong.Parse(input);

        Console.Clear();

        if(year < 1582)

        {

            Console.WriteLine("Leap years weren't recorded until after 1582.");

            goto start;

        }

        else if(year > 3000)

        {

            Console.WriteLine("Thats too far into the future for me to program... Sorry.");

            goto start;

        }

        ulong com = year%100;

        ulong leap = year%400;

        for (ulong i=4; i<5; i++)

        {

            ulong ans = year%i;

            if(com == 0 && leap != 0 || ans != 0)

            {

                Console.Write(input+ " is a common year.");

            }

            else if(com == 0 && leap == 0 || ans == 0)

            {

                Console.Write(input+ " is a leap year.");

            }

        }

        Console.WriteLine();

        Console.WriteLine();

        Console.WriteLine("Do you want to restart the program?");

        string choice = Console.ReadLine();

        if (choice == "y" || choice == "Y")

        {

            Console.Clear();

            goto start;

        }

    }

}