using System;

public class Program

{

    public static void Main()

    {

char ch;

    Console.WriteLine("enter your number");

        ch=Convert.ToChar(Console.ReadLine());

        switch(Char.ToLower(ch))

        {

            case 'a':

                Console.Write("Vowel");

                break;

                default:

                Console.Write("Not a vowel");

                break;

    }

}

}

​