using System;

public class Program

{

    public static void Main()

    {

        int chk_year;

        Console.Write("Nhap mot nam bat ky de kiem tra: ");

        chk_year = Convert.ToInt32(Console.ReadLine());

​

        if ((chk_year % 400) == 0)

            Console.WriteLine("{0} la nam nhuan.\n", chk_year);

        else if ((chk_year % 4) == 0 && (chk_year % 100) != 0)

            Console.WriteLine("{0} la nam nhuan.\n", chk_year);

        else

            Console.WriteLine("{0} khong phai la nam nhuan.\n", chk_year); 

    }

}