Lucky ticket

Every day Sam buys a ticket. On the ticket, there is a letter-code that can be represented as a string of upper-case letters.

Sam believes that the day will be successful in case exactly two different letters in the code alternate. Otherwise, he believes that the day will be unlucky.

You are given a ticket code. Please determine, whether the day will be successful for Sam or not. Print "YES" or "NO" (without quotes) corresponding to the situation.
        
       Input:-2
ABABAB
ABC
       Input Description: The first line of The input contains an integer T denoting The number of test cases. The description of T test cases follows.
-The first and only line of each test case contains a single string S denoting The letter code on The ticket. 
       Output: YES
NO
       Output Description: For each test case, output a single line containing "YES" (without quotes) in case the day will be successful and "NO" otherwise. 
       Constraints: 1 <= T <= 100
S consists only of upper-case letters
       Explanation:

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