Balanced String Verification

You are given a string S and an integer T. A string is defined to be balanced if in every prefix of the string, the frequency of every character does not exceed the threshold T.

For example, consider S = "abac" with T = 2:

• Prefix "a": frequency of 'a' = 1 ≤ 2
• Prefix "ab": frequency of 'a' = 1, 'b' = 1 ≤ 2
• Prefix "aba": frequency of 'a' = 2, 'b' = 1 ≤ 2
• Prefix "abac": frequency of 'a' = 2, 'b' = 1, 'c' = 1 ≤ 2

This string is balanced so the result is YES. If the threshold T is exceeded for any character in any prefix, then the string is not balanced and the answer is NO.

You need to process multiple queries. For each query, output YES if the string is balanced under the given threshold, otherwise output NO.

Note: In your solution, all formulas should be in LaTeX format. For example, the condition that the frequency of each character does not exceed T can be written in LaTeX as \(\text{frequency} \le T\).

inputFormat

The input is read from standard input (stdin) and has the following format:

1. An integer \(Q\) representing the number of queries.
2. Each of the next \(Q\) lines contains an integer \(T\) and a string \(S\) separated by a space.

outputFormat

For every query, print a line containing either YES if the string is balanced according to the given threshold \(T\), or NO if it is not.

## sample

3
2 abac
1 aa
3 aabbbcc

YES
NO
YES

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