description: 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").
solution: #include <bits/stdc++.h>
  void sort(char string[], int len);
  int main() {
    int tc;
    scanf("%d", &tc);
    for (int i = 0; i < tc; i++) {
      int len;
      scanf("%d", &len);
      char string[len];
      scanf("%s", &string);
      char dup[len];
      int l = 0;
      while (l < len) {
        dup[l] = string[l];
        l++;
      }
      sort(string, len);
      int count = 0;
      for (int i = 0; i < len; i++) {
        if (dup[i] != string[i]) {
          count++;
        }
      }
      printf("%d\n", count);
    }
    return 0;
  }
  void sort(char string[], int len) {
    for (int i = 0; i < len - 1; i++) {
      for (int j = 0; j < len - 1 - i; j++) {
        if (string[j] > string[j + 1]) {
          int temp;
          temp = string[j];
          string[j] = string[j + 1];
          string[j + 1] = temp;
        }
      }
    }
  }
  