using System;

public class Program

{

    public static  int[] arr = {1,2,3,4,4,5};

    public 

        static int id =1;

    public static void Main()

    {

        Console.WriteLine("Hello World");

        int value =Program.removeDuplicate();

        Console.WriteLine(value);

        for (int i = 0;i<value;i++)

        {

            Console.WriteLine(arr[i]);

        }

    }

    public static int removeDuplicate() {

        if(arr.Length <2)

        {

            id =1;

        }

        else {

            for(int i=1;i<arr.Length;i++) {

                if(arr[i-1]!=arr[i]) {

                    arr[id] = arr[i];

                    id++;

            }

        }

    }

        return id;

    }

}