Given a list of phone numbers, determine if it is valid list of numbers in the sense that no number is the prefix of another. Let’s say the phone catalogue listed these numbers:

• Emergency 911
• Sahil 97 625 999
• Trilok 91 12 54 26

In this case, it’s not possible to call Trilok, because the central would direct your call to the emergency line as soon as you had dialled the first three digits of Trilok's phone number. So this list would not be valid.

INPUT FORMAT :

The first line of input gives a single integer, 1 <= t <= 40, the number of test cases. Each test case starts with n, the number of phone numbers, on a separate line, 1 <= n <= 10000. Then follows n lines with one unique phone number on each line. A phone number is a sequence of at most ten digits.

OUTPUT FORMAT :

For each test case, output “YES” if the list is consistent, or “NO” otherwise in a newline.