title: Need help fixing and formatting my code in Python
body: <blockquote>
  <p>Primary U.S. interstate highways are numbered 1-99.<br />
  Odd numbers (like the 5 or 95) go north/south, and evens (like the 10 or 90) go east/west.<br />
  Auxiliary highways are numbered 100-999, and service the primary highway indicated by the rightmost two digits. Thus, I-405 services I-5, and I-290 services I-90.</p>
  </blockquote>
  <blockquote>
  <p>Given a highway number, indicate whether it is a primary or auxiliary highway. If auxiliary, indicate what primary highway it serves. Also indicate if the (primary) highway runs north/south or east/west.</p>
  </blockquote>
  <blockquote>
  <p>Ex: If the input is:<br />
  <code>90</code><br />
  the output is:<br />
  <code>I-90 is primary, going east/west.</code><br />
  Ex: If the input is:<br />
  <code>290</code><br />
  the output is:<br />
  <code>I-290 is auxiliary, serving I-90, going east/west.</code><br />
  Ex: If the input is:<br />
  <code>0</code><br />
  the output is:<br />
  <code>0 is not a valid interstate highway number.</code></p>
  </blockquote>
  <p><strong>My Code:</strong></p>
  <pre><code>highway_number = int(input(&quot;Enter highway number: &quot;))
  
  # output if the highway is invalid
  
  if  ((highway_number &lt;1) or (highway_number &gt;999)):
     print (' {} is not a valid highway number'.format (highway_number))
  else: # valid
  
     if (highway_number &gt;99):
        print ( ' I-{} is a auxillary highway '.format (highway_number))
  # serves the primary interstate highway
     primary_number = highway_number % 100
  
  print (' serving I-{}'.format(primary_number))
  else: # must be 1-99 and it is  primary interstate highway
  primary_interstate_highway = highway_number
  print (' I-{} is a primary interstate highway'.format(highway_number))
  # direction
  
  if (primary_interstate_highway %2) == 0): #Event
  print('going east/west')
  else: #odd
  print('going south/north')
  </code></pre>
  <p>This is where the error is currently.</p>
  <p><img src="https://i.stack.imgur.com/nWMEf.png" alt="" /></p>