using System;

using System.Globalization;

public class Program

{

    public static void Main()

    {     

    string s = null;

    char[] characters = "abcdefghi".ToCharArray();

   // string[] words = s.Split(char[])

    foreach (char word in characters)

    {

       s += word+",";

    }

     Console.WriteLine(s);

    }   

}