using System;

public class Program

{

    public static void Main()

    {

         Console.Write("Enter your grade : ");

        string grade = Console.ReadLine().ToUpper();

​

        switch (grade)

        {

            case "A":

            case "B":

                Console.WriteLine("Well done!");

                break;

            case "C":

                Console.WriteLine("Room for improvement.");

                break;

            default:

                Console.WriteLine("Try harder.");

                break;

        }

    }

}