using System;

public class Program

{

    public static void Main()

    {

        int prevCh = Console.Read();

        if ( prevCh == -1 || prevCh == '\r' || prevCh == '\n')

        {

        }

        else

        {

            while (true)

            {

                int ch =Console.Read();

                if (ch == -1 || ch == '\r' || ch == '\n')

                {

                    break;

                }

                else

                {

                    if (ch != prevCh)

                    {

                        Console.Write(ch);

                        prevCh = ch;

                    }

                }

            }

        }

​

    }

}