#include <bits/stdc++.h>
using namespace std;
inline long long toint(string s) {
  long long v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class T>
inline string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}
template <class T>
inline T sqr(T x) {
  return x * x;
}
const double EPS = 1e-10;
const double PI = acos(-1.0);
const long long INF = 4e18;
const long long NINF = 1 - INF;
struct POINT {
  double x;
  double y;
};
long long gcd(long long x, long long y) { return y ? gcd(y, x % y) : x; }
long long lcm(long long a, long long b) { return (a / gcd(a, b)) * b; }
long long nCr(long long n, long long r) {
  if (r * 2 > n) r = n - r;
  long long dividend = 1;
  long long divisor = 1;
  for (unsigned int i = 1; i <= r; ++i) {
    dividend *= (n - i + 1);
    divisor *= i;
  }
  return dividend / divisor;
}
template <class T>
pair<T, long long> maxP(vector<T> a, long long size) {
  pair<T, long long> p;
  long long ind = 0;
  T mx = NINF;
  for (long long i = (0); i < (size); ++i) {
    if (mx < a[i]) {
      mx = a[i];
      ind = i;
    }
  }
  p.first = mx;
  p.second = ind;
  return p;
}
template <class T>
pair<T, long long> minP(vector<T> a, long long size) {
  pair<T, long long> p;
  T mn = INF;
  long long ind = 0;
  for (long long i = (0); i < (size); ++i) {
    if (mn > a[i]) {
      mn = a[i];
      ind = i;
    }
  }
  p.first = mn;
  p.second = ind;
  return p;
}
template <class T>
T sumL(vector<T> a, long long size) {
  T sum = 0;
  for (long long i = (0); i < (size); ++i) {
    sum += a[i];
  }
  return sum;
}
long long counT(vector<long long> a, long long left, long long right,
                long long t) {
  return upper_bound(a.begin() + left, a.begin() + right, t) -
         lower_bound(a.begin() + left, a.begin() + right, t);
}
long long kiriage(long long a, long long b) { return a / b + (a % b != 0); }
long long search(vector<long long> &a, long long n) {
  std::vector<long long>::iterator iter = std::find(a.begin(), a.end(), n);
  size_t index = distance(a.begin(), iter);
  return index;
}
int getdigit(long long n) { return log10(n) + 1; }
vector<long long> toBinary(long long bina) {
  vector<long long> ans;
  for (long long i = 0; bina > 0; i++) {
    ans.push_back(bina % 2);
    bina = bina / 2;
  }
  return ans;
}
long long n, m;
long long h, w, k;
string s;
vector<long long> A, B;
map<long long, long long> p;
long long v, e;
int main() {
  int N;
  cin >> N;
  for (long long i = (0); i < (N); ++i) {
    long long k;
    cin >> k;
    string s;
    cin >> s;
    vector<long long> a(k);
    for (long long j = (0); j < (k); ++j) {
      a[j] = s[j];
    }
    long long ans = 0;
    sort((a).begin(), (a).end());
    for (long long j = (0); j < (k); ++j) ans += s[j] != a[j];
    cout << ans << endl;
  }
  return 0;
}

### Prompt

Please provide a CPP coded solution to the problem described below:

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;
inline long long toint(string s) {
  long long v;
  istringstream sin(s);
  sin >> v;
  return v;
}
template <class T>
inline string toString(T x) {
  ostringstream sout;
  sout << x;
  return sout.str();
}
template <class T>
inline T sqr(T x) {
  return x * x;
}
const double EPS = 1e-10;
const double PI = acos(-1.0);
const long long INF = 4e18;
const long long NINF = 1 - INF;
struct POINT {
  double x;
  double y;
};
long long gcd(long long x, long long y) { return y ? gcd(y, x % y) : x; }
long long lcm(long long a, long long b) { return (a / gcd(a, b)) * b; }
long long nCr(long long n, long long r) {
  if (r * 2 > n) r = n - r;
  long long dividend = 1;
  long long divisor = 1;
  for (unsigned int i = 1; i <= r; ++i) {
    dividend *= (n - i + 1);
    divisor *= i;
  }
  return dividend / divisor;
}
template <class T>
pair<T, long long> maxP(vector<T> a, long long size) {
  pair<T, long long> p;
  long long ind = 0;
  T mx = NINF;
  for (long long i = (0); i < (size); ++i) {
    if (mx < a[i]) {
      mx = a[i];
      ind = i;
    }
  }
  p.first = mx;
  p.second = ind;
  return p;
}
template <class T>
pair<T, long long> minP(vector<T> a, long long size) {
  pair<T, long long> p;
  T mn = INF;
  long long ind = 0;
  for (long long i = (0); i < (size); ++i) {
    if (mn > a[i]) {
      mn = a[i];
      ind = i;
    }
  }
  p.first = mn;
  p.second = ind;
  return p;
}
template <class T>
T sumL(vector<T> a, long long size) {
  T sum = 0;
  for (long long i = (0); i < (size); ++i) {
    sum += a[i];
  }
  return sum;
}
long long counT(vector<long long> a, long long left, long long right,
                long long t) {
  return upper_bound(a.begin() + left, a.begin() + right, t) -
         lower_bound(a.begin() + left, a.begin() + right, t);
}
long long kiriage(long long a, long long b) { return a / b + (a % b != 0); }
long long search(vector<long long> &a, long long n) {
  std::vector<long long>::iterator iter = std::find(a.begin(), a.end(), n);
  size_t index = distance(a.begin(), iter);
  return index;
}
int getdigit(long long n) { return log10(n) + 1; }
vector<long long> toBinary(long long bina) {
  vector<long long> ans;
  for (long long i = 0; bina > 0; i++) {
    ans.push_back(bina % 2);
    bina = bina / 2;
  }
  return ans;
}
long long n, m;
long long h, w, k;
string s;
vector<long long> A, B;
map<long long, long long> p;
long long v, e;
int main() {
  int N;
  cin >> N;
  for (long long i = (0); i < (N); ++i) {
    long long k;
    cin >> k;
    string s;
    cin >> s;
    vector<long long> a(k);
    for (long long j = (0); j < (k); ++j) {
      a[j] = s[j];
    }
    long long ans = 0;
    sort((a).begin(), (a).end());
    for (long long j = (0); j < (k); ++j) ans += s[j] != a[j];
    cout << ans << endl;
  }
  return 0;
}

```