using System;

using System.Text;

public class Program

{

    public static void Main()

    {

        string data = "1218843294";

        StringBuilder sb = new StringBuilder();

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

        {

          if (i % 2 > 0 || i == 0)

            sb.Append(data[i]);

          else

            sb.Append(" " + data[i]);

        }

        Console.WriteLine(sb.ToString());

    }

}