public class Program
{
    public static void Main()
    {
        //int num = int.Parse(Console.ReadLine() ?? string.Empty);
        //string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        string str = Console.ReadLine() ?? string.Empty;

        string k = "";

        int cou = 0;
        for (int i = str.Length - 1; i >= 0; i--)
        {
            k += str[i];
            cou++;
            if (cou % 3 == 0 && i != 0)
            {
                k += ",";
            }

        }
        for (int i = k.Length - 1; i >= 0; i--)
        {
            Console.Write(k[i]);
        }
        Console.WriteLine();
    }
}