#include <bits/stdc++.h>
using namespace std;
const int MAX = 1e6 + 5;
const int MOD = 1e9 + 7;
int dr[4] = {0, 0, 1, -1};
int dc[4] = {1, -1, 0, 0};
int ddr[8] = {0, 0, 1, -1, 1, -1, 1, -1};
int ddc[8] = {1, -1, 0, 0, 1, -1, -1, 1};
bool isPrime(int n) {
  if (n <= 1) return false;
  for (int i = 2; i < n; i++)
    if (n % i == 0) return false;
  return true;
}
long long int power(long long int a, long long int b) {
  long long int ans = 1;
  while (b) {
    if (b & 1) ans = (ans * a) % MOD;
    a = (a * a) % MOD;
    b /= 2;
  }
  return ans;
}
long long int nCr(long long int n, long long int r) {
  long long int ans = 1, i;
  if (r > n - r) r = n - r;
  for (i = 0; i < r; i++) {
    ans = (ans * (n - i)) % MOD;
    ans = (ans * power(i + 1, MOD - 2)) % MOD;
  }
  return ans;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int t;
  t = 1;
  cin >> t;
  int tt = 0;
  while (t--) {
    int n, k;
    cin >> n >> k;
    string s;
    cin >> s;
    int a = k / 3;
    a++;
    string r;
    for (int i = 0; i < a; i++) {
      r = r + "RGB";
    }
    r = r + "RGB";
    int mn = 1e5;
    for (int i = 0; i < n - k + 1; i++) {
      int mm = 1e5;
      string p = s.substr(i, k);
      int c = 0, d = 0, e = 0;
      for (int j = 0; j < k; j++) {
        if (p[j] != r[j]) c++;
        if (p[j] != r[j + 1]) d++;
        if (p[j] != r[j + 2]) e++;
      }
      mm = min(c, min(d, e));
      mn = min(mn, mm);
    }
    cout << mn << "\n";
  }
  return 0;
}
