using System;

using System.Linq;

using System.Xml;                   

using System.Xml.Linq;

using System.Collections; 

using System.Collections.Generic;

using System.Data;

using System.Data.DataSetExtensions;

using System.Data.Linq;

using System.Text;

using System.Text.RegularExpressions;

using System.Xml.Serialization; 

using System.IO;

public class Program

{

    public static void Main()

    {

        string[] s = new string[] { "a", "a", "a", "b", "b", "c", "c", "c"};

        s = s.GroupBy(x=>x)

               .SelectMany(x=>x.Take(1)

                         .Concat(x.Skip(1).Select(r=>"Duplicate"))

                     )

               .ToArray();  

        s.Dump();

    }

}