using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        string input = "This,is,an,example,for,the,stackoverflow,community";

        var output = input.Split(",")

            .Chunk(2)

            .Select(chunk => string.Join(",", chunk));

        foreach (string s in output)

            Console.WriteLine(s);

    }

}