python练习题

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userername = raw_input("USERNAME:")

password = raw_input("PASSWORD:")

if username == "user" and password == "123":

  print "welcome"

  break

elif username != "user" and password != "123":

  print "username and password mistakes"

elife username == "user" and password != "123":

  print "password mistakes"

elife username != "user" and password == "123":

  print "username mistakes"