using System;

public class Program

{

    public static void Main()

    {

        int mark;

        Console.WriteLine("Enter Mark");

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

        if(mark>=80&&mark<=100)

        {

            Console.WriteLine("A Grade");

        }

        else if(mark>=60&&mark<=79)

        {

            Console.WriteLine("B grade");

        }

        else if(mark>=35&&mark<=59)

        {

            Console.WriteLine("C grade");

        }

        else

        {

            Console.WriteLine("Better Luck Next time");

        }

        }

}