#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
#define ll long long int
#define ull unsigned long long int
#define ld long double
#define endl '\n'
#define loop(a,b,c) for(ll i=a;i<=b;i+=c)
#define intarr(arr,n) ll arr[n];for(ll i=0;i<n;i++)cin>>arr[i]
#define inparr(arr,n) for(ll i=0;i<n;i++)cin>>arr[i]
#define inpvec(vec,n) for(ll i=0;i<n;i++){ll var;cin>>var;vec.push_back(var);}
#define pb push_back
#define fastio ios_base::sync_with_stdio(false);cin.tie(NULL);
#define mod 1000000007
#define newline cout<<endl
#define ump unordered_map<ll,ll>
#define vec vector<ll>
#define mkp make_pair
#define disp(var1,var2) cout<<var1<<" "<<var2<<endl;
#define all(v)             v.begin(),v.end()
#define cout(var) cout<<var<<endl
#define mod2 998244353
#define fbo find_by_order  /// find kth smallest by passing k-1
#define ook order_of_key  //// find no of smaller items less than k
#define teensort(a,r,g,b) a[0]=r;a[1]=g;a[2]=b;sort(a,a+3);
#define ss second
#define ff first
#define displayarray(a,n) for(ll i=0;i<n;i++)cout<<a[i]<<" "; cout<<endl;
#define pi pair<ll,ll>
#define meramax 1e18
#define meramin -1e18
#define percentile 1000000007
#define PI 3.14159265358979323846
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////                                     ///////////////////////////////////////////////////////////////
////////////////////////////////////////              CODE                   ///////////////////////////////////////////////////////////////
////////////////////////////////////////                                     ///////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// 
void AcDegaYe()
{
    ll n,k;
    cin>>n>>k;
    string s;
    cin>>s;
    if(k==1)
    {
        cout(0);
        return;
    }
    if(k==2)
    {
        if(s.find("RG")!=string::npos || s.find("GB")!=string::npos || s.find("BR")!=string::npos)
        {
            cout(0);
        }
        else
        {
            cout(1);
        }
        return;
    }
    string s1="RGB";
    string s2="GBR";
    string s3="BRG";
    for(ll i=3;i<k;i++)
    {
        s1[i]=s1[i-3];
        s2[i]=s2[i-3];
        s3[i]=s3[i-3];
    }
    ll ans=INT_MAX;
    for(ll i=0;i<=n-k;i++)
    {
        ll cnt1=0,cnt2=0,cnt3=0;
        string ss=s.substr(i,k);
        for(ll j=0;j<k;j++)
        {
            if(ss[j]!=s1[j])
            {
                cnt1++;
            }
            if(ss[j]!=s2[j])
            {
                cnt2++;
            }
            if(ss[j]!=s3[j])
            {
                cnt3++;
            }
        }
        //cout<<cnt1<<cnt2<<cnt3<<endl;
        ans=min({ans,cnt1,cnt2,cnt3});
    }
    cout(ans);
}
int main()
{   
    
    fastio
    ll t;
    cin>>t;
    //ll t=1;
    while(t--)
    {
        AcDegaYe();
    }
    cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    return 0;
}