human
A string s of length n, consisting of lowercase letters of the English alphabet, is given.

You must choose some number k between 0 and n. Then, you select k characters of s and permute them however you want. In this process, the positions of the other n-k characters remain unchanged. You have to perform this operation exactly once.

For example, if s="andrea", you can choose the k=4 characters "a_d_ea" and permute them into "d_e_aa" so that after the operation the string becomes "dneraa".

Determine the minimum k so that it is possible to sort s alphabetically (that is, after the operation its characters appear in alphabetical order).

Input

The first line contains a single integer t (1 ≤ t ≤ 1000) — the number of test cases. Then t test cases follow.

The first line of each test case contains one integer n (1 ≤ n ≤ 40) — the length of the string.

The second line of each test case contains the string s. It is guaranteed that s contains only lowercase letters of the English alphabet.

Output

For each test case, output the minimum k that allows you to obtain a string sorted alphabetically, through the operation described above.

Example

Input

4
3
lol
10
codeforces
5
aaaaa
4
dcba

Output

2
6
0
4

Note

In the first test case, we can choose the k=2 characters "_ol" and rearrange them as "_lo" (so the resulting string is "llo"). It is not possible to sort the string choosing strictly less than 2 characters.

In the second test case, one possible way to sort s is to consider the k=6 characters "_o__force_" and rearrange them as "_c__efoor_" (so the resulting string is "ccdeefoors"). One can show that it is not possible to sort the string choosing strictly less than 6 characters.

In the third test case, string s is already sorted (so we can choose k=0 characters).

In the fourth test case, we can choose all k=4 characters "dcba" and reverse the whole string (so the resulting string is "abcd").
The above is tricky. Write me a correct solution in PYTHON3.

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Give me a Python program to determine the minimum k so that it is possible to sort s alphabetically (that is, after the operation its characters appear in alphabetical order)?
assistant
#Here is Python program to determine the minimum k so that it is possible to sort s alphabetically (that is, after the operation its characters appear in alphabetical order).

t = int(input())
l = []; a = []
for i in range(t):
   rem = input()
   l.append(str(input()))
for i in l:
    def split(i):
       temp = [x for x in i]
       temp.sort()
       return "".join(temp)
    a.append(split(i))
for i,j in zip(l,a):
    c = 0
    for x in range(len(i)):
        if i[x] != j[x]: c += 1
    print(c)