using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Enter a number  ");

        int n =Int32.Parse(Console.ReadLine());

        int m=n;

        int r=0;

        int count=0;

        while(n>0)

         {

             r=n%2;

             count++;

              n=n/2; 

         }

        int[] arr=new int[count];

        int i=0;

        while(m>0)

         {

             r=m%2;

             arr[i]=r;

               i++;

              m=m/2; 

         }

        for(int j=count-1;j>=0;j--)

        {

            Console.Write(arr[j]);

        }

    }

}

​

​

​