There is a string that consists of lowercase english alphabets and we have to make the string a palindrome
For this, we have $2$ types of operations
1. Re-arrange the string however you want (this operation is free)
2. Add a new character to the end of the string (this operation will cost 1Re)

Your task is to calculate the minimum amount of money to make the string a palindrome

Input Format:
The first line contains one integer $T$ the number of test cases
The first line of every test case consists of $N$, the length of the string 
The second line of every test case contains string $S$

Output Format:
For every test case output one integer, the minimum amount of money required to make the string a palindrome

Constraints:

$1 \leq T \leq 100 \\ 1 \leq N \leq 10^5$