Recently Brother.R has designed a BBS. Everyday there are many people register or login or logout.You are asked to help deal with these requests.There are three different requests, "register", "login", "logout". "register". If the username is already existent, return "User existed!", otherwise return "Congratulations, xxx!".(xxx is the new username) "login". If the username is not existent or the password is not correct, return "Invalid user or password!". otherwise return "Welcome xxx!".(xxx is the username) User can login many times. "logout". Just return "Goodbye xxx!".(xxx the username) You can assume that this user is on-line. Every string will only contain lower-case letter or digit, and the range of its length is [1, 10]. Initially there is no user.

The first line is integer N(N <= 20), the number of test requests. Then N lines, each line is one of three formats below: register str1 str2 (str1 is the username and str2 is the password). login str1 str2 (str1 is the username and str2 is the password). logout str1 (str1 is the username).

For each request, print the corresponding reply.

wangyao