using System;

using System.IO;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var tmpList = new List<string>{ "Houseplant" };

        tmpList = tmpList.Select(hashtag => String.Concat("#", hashtag)).ToList();

        foreach(var item in tmpList)

            Console.WriteLine(item);

    }

}