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CF1766B.Notepad#
Notepad#
You want to type the string , consisting of lowercase Latin letters, using your favorite text editor Notepad#.
Notepad# supports two kinds of operations:
- append any letter to the end of the string;
- copy a continuous substring of an already typed string and paste this substring to the end of the string.
Can you type string in strictly less than operations?
Input
The first line contains a single integer () — the number of testcases.
The first line of each testcase contains a single integer () — the length of the string .
The second line contains a string , consisting of lowercase Latin letters.
The sum of doesn't exceed over all testcases.
Output
For each testcase, print "YES" if you can type string in strictly less than operations. Otherwise, print "NO".
Note
In the first testcase, you can start with typing "codef" ( operations), then copy "o" ( operation) from an already typed part, then finish with typing "rces" ( operations). That will be operations, which is not strictly less than . There exist other ways to type "codeforces". However, no matter what you do, you can't do less than operations.
In the second testcase, you can type "labac" ( operations), then copy "aba" ( operation), finishing the string in operations.
Samples
6
10
codeforces
8
labacaba
5
uohhh
16
isthissuffixtree
1
x
4
momo
NO
YES
NO
YES
NO
YES
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