username=["defualt":123]
print "welcome"
val=raw_input(" Enter 1 if you are new 2 if you have a login")
if val=="1":
    name=raw_input("user name?:")
    name in username
    while name in username:
            print "Username has already been taken,"
            name=raw_input("please try again")



    else:
        username.append(name)
        password=raw_input("password?: ")
        repass= raw_input("re-type password?: ")
        repass in password
        if repass == password:
            print "username and password set"
        else:
            print "passwords do not match"