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").


import java.io.IOException;
import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) throws IOException {
		
		Scanner scanner=new Scanner(System.in);
		long t=scanner.nextLong();
		for(int i=1;i<=t;i++) {
			int n=scanner.nextInt();
			String s=scanner.next();
			System.out.println(subPerm(s));
		}
		

	}
	
public static void burles(long n) {
	
	long x=n/3;
	long k=n%3;
	long c1=x;
	long c2=x;
	if(k==2)c2++;
	else if(k==1)c1++;
	System.out.println(c1+" "+c2);
}

public static long interesting(long x){
	long n=x/10;
	x%=10;
	if(x==9)n++;
	return n;
}
	
public static int subPerm(String s) {
	int sum=0;
	char[] ch = s.toCharArray();
	char []k=Arrays.copyOf(ch,ch.length);
	Arrays.sort(ch);
	System.out.println(ch);
	System.out.println(k);
	for(int i=0;i<ch.length;i++) {
		if(ch[i]!=k[i])sum++;
	}
	return sum;
}

}
