CF1628B Peculiar Movie Preferences

Mihai plans to watch a movie. He only likes palindromic movies, so he wants to skip some (possibly zero) scenes to make the remaining parts of the movie palindromic. You are given a list $ s $ of $ n $ non-empty strings of length at most $ 3 $ , representing the scenes of Mihai's movie. A subsequence of $ s $ is called awesome if it is non-empty and the concatenation of the strings in the subsequence, in order, is a palindrome. Can you help Mihai check if there is at least one awesome subsequence of $ s $ ? A palindrome is a string that reads the same backward as forward, for example strings "z", "aaa", "aba", "abccba" are palindromes, but strings "codeforces", "reality", "ab" are not. A sequence $ a $ is a non-empty subsequence of a non-empty sequence $ b $ if $ a $ can be obtained from $ b $ by deletion of several (possibly zero, but not all) elements.

The first line of the input contains a single integer $ t $ ( $ 1 \le t \le 100 $ ) — the number of test cases. The description of test cases follows. The first line of each test case contains a single integer $ n $ ( $ 1 \le n \le 10^5 $ ) — the number of scenes in the movie. Then follows $ n $ lines, the $ i $ -th of which containing a single non-empty string $ s_i $ of length at most $ 3 $ , consisting of lowercase Latin letters. It is guaranteed that the sum of $ n $ over all test cases does not exceed $ 10^5 $ .

For each test case, print "YES" if there is an awesome subsequence of $ s $ , or "NO" otherwise (case insensitive).

In the first test case, an awesome subsequence of $ s $ is $ [ab, cc, ba] $