using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        List<string> listStr = new List<string>();

        listStr.Add("aaa");

        listStr.Add("bbb");

        Console.WriteLine("test");

        Console.WriteLine(string.Join(",", listStr));

        Console.WriteLine("test2");

        List<string> listStr2 = new List<string>();

        listStr2.Add("aaa");

        listStr2.Add("bbbc");

        Console.WriteLine(string.Join(",", listStr2));

    }

}