#include <bits/stdc++.h>
using namespace std;
string to_string(char c) { return "'" + string(1, c) + "'"; }
string to_string(string s) { return '"' + s + '"'; }
string to_string(bool f) {
  if (f)
    return "True";
  else
    return "False";
}
string to_string(const char *s) { return to_string((string)s); }
template <typename A>
string to_string(A);
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ": " + to_string(p.second) + ")";
}
template <typename A>
string to_string(A v) {
  bool f = false;
  string r = "{";
  for (auto x : v) {
    if (f) r += ", ";
    r += to_string(x);
    f = true;
  }
  return r += "}";
}
template <typename A>
string to_string(vector<vector<A>> v) {
  string r;
  for (auto x : v) r += "\n" + to_string(x);
  return r;
}
long long Nerr;
template <typename A>
string to_string(A *p) {
  return to_string(vector<A>(p, p + Nerr));
}
void err(istream_iterator<string>) { cerr << '\n'; }
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << to_string(a) << "; ";
  err(++it, args...);
}
template <typename T>
void kek(T ans) {
  cout << ans << '\n';
  exit(0);
}
signed main() {
  ios_base::sync_with_stdio(0);
  long long TESTS = 1;
  cin >> TESTS;
  while (TESTS--) {
    long long n;
    cin >> n;
    string s;
    cin >> s;
    string t = s;
    sort((t).begin(), (t).end());
    long long diff = 0;
    for (long long i = 0; i < (long long)s.size(); i++)
      if (s[i] != t[i]) diff++;
    cout << diff << '\n';
  }
}

### Prompt

Please formulate a cpp solution to the following problem:

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").

### Response

```cpp
#include <bits/stdc++.h>
using namespace std;
string to_string(char c) { return "'" + string(1, c) + "'"; }
string to_string(string s) { return '"' + s + '"'; }
string to_string(bool f) {
  if (f)
    return "True";
  else
    return "False";
}
string to_string(const char *s) { return to_string((string)s); }
template <typename A>
string to_string(A);
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ": " + to_string(p.second) + ")";
}
template <typename A>
string to_string(A v) {
  bool f = false;
  string r = "{";
  for (auto x : v) {
    if (f) r += ", ";
    r += to_string(x);
    f = true;
  }
  return r += "}";
}
template <typename A>
string to_string(vector<vector<A>> v) {
  string r;
  for (auto x : v) r += "\n" + to_string(x);
  return r;
}
long long Nerr;
template <typename A>
string to_string(A *p) {
  return to_string(vector<A>(p, p + Nerr));
}
void err(istream_iterator<string>) { cerr << '\n'; }
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << to_string(a) << "; ";
  err(++it, args...);
}
template <typename T>
void kek(T ans) {
  cout << ans << '\n';
  exit(0);
}
signed main() {
  ios_base::sync_with_stdio(0);
  long long TESTS = 1;
  cin >> TESTS;
  while (TESTS--) {
    long long n;
    cin >> n;
    string s;
    cin >> s;
    string t = s;
    sort((t).begin(), (t).end());
    long long diff = 0;
    for (long long i = 0; i < (long long)s.size(); i++)
      if (s[i] != t[i]) diff++;
    cout << diff << '\n';
  }
}

```