import java.io.*;

public class GetBinaryMain
{
	public static void main (String[ ] args) 
	{      
     		try
     		{
        		final String PROMPT = "Please enter a base-10, non-negative integer: ";

        		final String RESULT = "The binary equivalent is ";

        		BufferedReader reader = new BufferedReader
                                        		(new InputStreamReader (System.in));

        		System.out.print (PROMPT);
        		int n = Integer.parseInt (reader.readLine());
        		System.out.print (RESULT + getBinary (n)); // RA1        
     		} // try
     		catch (IOException e)
     		{
			System.out.println (e);
     		} // catch
     		catch (IllegalArgumentException e)
     		{
			System.out.println (e);
     		} // catch

	} // method main

	/**
	 *
	 * Determines the binary equivalent of a non-negative integer.  The worstTime(n)
	 * is O(log n), where n is the given integer.
	 *
	 * @param n the non-negative integer, in decimal notation.
	 *
	 * @return a String representation of the binary equivalent of n.
	 *	 
	 * @throws  IllegalArgumentException if n is negative.
	 */
	public static String getBinary (int n) 
	{
 		if (n < 0)
	              	throw new IllegalArgumentException();
       		if (n <= 1)
          		return Integer.toString (n);
       		return getBinary (n / 2) + Integer.toString (n % 2);
 	} // method getBinary

} // class GetBinaryMain