using System;

using System.IO;

public class Program

{

    static string input=@"<Triangle>,1,2,3

<Rectangle>,4,2

<Square>,3

<Rectangle>,4,3

<Circle>,2

<End>

";

    public static void Main()

    {

        int i=0;

        string s;

        using (StringReader sr=new StringReader(input))

        {

            while ((s=sr.ReadLine())!=null)

            {

            i++;

            Console.WriteLine($"{i} : {s}");

            }

        }

        Console.WriteLine("Done");

    }

}

​