[Tutor] urllib problem

[Roelof Wobben]

Hoi, 
 
I have this programm :
 
import urllib
import re
f = urllib.urlopen("http://www.pythonchallenge.com/pc/def/linkedlist.php?nothing=6")
inhoud = f.read()
f.close()
nummer = re.search('[0-9]', inhoud)
volgende = int(nummer.group())
teller = 1 
while teller <= 3 :
      url = "http://www.pythonchallenge.com/pc/def/linkedlist.php?nothing=" + str(volgende)
      f = urllib.urlopen(url)
      inhoud = f.read()
      f.close()
      nummer = re.search('[0-9]', inhoud)
      print "nummer is", nummer.group()
      volgende = int(nummer.group())
      print volgende
      teller = teller + 1
 
but now the url changes but volgende not.
 
What do I have done wrong ?
 
Roelof