Can someone help me and tell why this does not work.

 

prys=0
tp=0
pr=0

f = open('C:\Documents and Settings\ZU1TN\Desktop\Nommers\K55.txt', 'r')

pr=f.readline()
prys =int(prys)
tp =int(tp)
pr =int(pr)
tp=pr-prys
f.close
tp=str(tp)
print tp

raw_input()

 

THX