K-Frequent Characters Count

You are given an integer n which represents the length of a string s, the string s itself, and an integer k. Your task is to determine the number of distinct characters in s that occur exactly k times.

Input Format: The input begins with an integer T on a new line representing the number of test cases. For each test case, there are three lines: the first line contains the integer n, the second line contains the string s, and the third line contains the integer k.

Output Format: For each test case, output a single integer on a new line corresponding to the count of characters in s that appear exactly k times.

Examples:

Input:
3
6
 aabbcc
2
4
 abcd
1
5
 aaaaa
3
Output:
3
4
0

</p>

inputFormat

The first line of input contains an integer T denoting the number of test cases. Each test case consists of three subsequent lines:

1. An integer n representing the length of the string s.
2. A string s consisting of lowercase/uppercase letters.
3. An integer k indicating the frequency to check.

Note: The value n is provided for informational purposes and may be ignored during processing.

outputFormat

For each test case, print the count of characters in the string s that appear exactly k times. Each answer should be printed on a separate line.

## sample

3
6
aabbcc
2
4
abcd
1
5
aaaaa
3

3
4
0

</p>