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").
/* package codechef; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

/* Name of the class has to be "Main" only if the class is public. */
public class Main
{
    static int mod = 998244353 ;
    static int factorial(int n){    
      if (n == 0)    
        return 1;    
      else    
        return(n * factorial(n-1))%mod;    
    }    
    
	public static void main (String[] args) throws java.lang.Exception
	{
        // uncomment this line if you want to use the txt file to take input
        //FileReader fr=new FileReader("D:\\test.txt");    
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        int t = Integer.parseInt(br.readLine());
        while(t-- != 0){
            int n = Integer.parseInt(br.readLine());
            // String[] str = br.readLine().split(" ");
            String str = br.readLine();
            
            int res = 0;
            for(int i = 0; i < n; i++){
                char ch = str.charAt(i);
                int l = 0, r = 0;
                for(int j = i+1; j < n; j++){
                    if(str.charAt(j) < ch) r++;
                }
                for(int j = i-1; j >= 0; j--){
                    if(str.charAt(j) > ch) l++;
                }
                
                if(l != r) res++;
            }
            
            System.out.println(res);
        }
	}
	
}
