using System;

public class Program

{

    public static void Main()

    {

        int[] arr=new int[6]{2,3,6,8,9,1};

        Console.WriteLine("Enter your number");

        int n=int.Parse(Console.ReadLine());

        int f=0;int l=arr.Length-1;int m=(f+l)/2;

        while(f<=l)

        {

            if(arr[m]<n)

            {

                f=m+1;

            }

            else if(arr[m]==n)

            {

                Console.Write("location found:"+m);

                break;

            }

            else

            {

            l=m-1;

            }

        m=(f+l)/2;

        }

        if(f>l)

        {

            Console.Write("not found",n);

        }

        Console.ReadLine();

    }

}