#################
############
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"
