using System;

public class Program

{

    public static void Main()

    {

        //зад.2

        string[] name = Console.ReadLine().Split(',');

        for(int i=0; i<name.Length; i++) 

        {

            if(name[i].Length == 4)

            {

                Console.Write(name[i] + ",");

            }

        }

    }

}