Problem with Switch case in Console Application

Hi all,

    i have a dout for given program which is developed by console application , the thing is please see my below code in that program i got output that is when i enter 70 it showing you are distinction ,and 50 you are failed.but my question is i just want to display the whole input without entering any value,

i need the given output,

1.you are distinction

2.average

3.failed

so what i change in my code or what i initialize in the  given apps, please let me know if any solution about this..

my code is

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            int mark;
            Console.WriteLine("enter the mark");
            mark = Convert.ToInt32(Console.ReadLine());
            switch (mark)
            {
                case 70:
                    Console.WriteLine(" you are distinction");
                    Console.ReadLine();
                    break;
                case 60:
                    Console.WriteLine("Average");
                    Console.ReadLine();
                    break;
                case 50:
                    Console.WriteLine("failed");
                    Console.ReadLine();
                    break;
            }
        }
    }
}

with regards,

stellus.