[Python-ideas] Help!!please

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