Not

 public class not

{
    public static void main ( String [] args)
    {
      int x;
        for ( x = 1; x <= 20; x = x+1)
        {
            System.out.println( x );
            
            if ( x % 2 == 0 )
            {
                System.out.println(" < ");
            }
        }
    }
}
    

Picture of the output