#include <algorithm>
#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <cstring>
#include <ctime>
#include <cassert>
using namespace std;
typedef long long LL;
#define FOR(k,a,b) for(int k(a); k < (b); ++k)
#define FORD(k,a,b) for(int k(b-1); k >= (a); --k)
#define REP(k,a) for(int k=0; k < (a); ++k)
#define ABS(a) ((a)>0?(a):-(a))

int main( int argc, char* argv[] ) {
#ifdef HOME
	freopen("in.txt","r",stdin);
	freopen("out.txt","wb",stdout);
#endif
	int T,N,K;
	scanf("%d",&T);
	char C[100002];
	bool b[100002];
	while(T--)
	{
		scanf("%d %d",&N,&K);
		scanf("%s",C);
		assert(strlen(C)==N);
		memset(b,0,sizeof b);
		int state = 0;
		int ans = 0;
		REP(i,N)
		{
			if(b[i])
				state = 1 - state;
			if((state == 0 && C[i]=='R') || (state == 1 && C[i]=='G'))
			{
				b[min(N,i+K)]=1;
				++ans;
				state = 1 - state;
			}
		}
		printf("%d\n",ans);
	}
	return 0;
}