#include <bits/stdc++.h>

#define PB push_back

#define MP make_pair

using namespace std;

typedef long long LL;

typedef pair<int,int> PII;

#define PI acos((double)-1)

#define E exp(double(1))

#define K 1000000+9

struct node1

{

    int h,kind;

}mp[K];

int n,m;

char ss[K];

struct node

{

    int mi;

    int left,right;

}tree[*K];

int build(int id,int l,int r)

{

    tree[id].left=l;tree[id].right=r;

    if(l==r)

        tree[id].mi=mp[l].h;

    else

    {

        build(*id,l,(l+r)/);

        build(*id+,(l+r)/+,r);

        tree[id].mi=min(tree[*id].mi,tree[*id+].mi);

    }

    return ;

}

int query(int id,int l,int r)

{

    if(l==tree[id].left && r==tree[id].right)

        return tree[id].mi;

    int mid=(tree[id].left+tree[id].right)>>;

    int ret=0x3f3f3f3f;

    if(r<=mid)

        ret=min(ret,query(id*,l,r));

    else if(l>=mid+)

        ret=min(ret,query(id*+,l,r));

    else

    {

        int a,b;

        a=query(id<<,l,mid);

        b=query((id<<)+,mid+,r);

        return min(a,b);

    }

    return ret;

}

double get_ans(int x,int mi)

{

    double ans=;

    ans+=mp[x].h-mi;

    ans+=mp[x].kind==?:0.5;

    return ans;

}

int main(void)

{

    int t,cs=;cin>>t;

    while(t--)

    {

        double ans,sum=;

        scanf("%d%d%s",&n,&m,&ss[]);

        mp[].h=;

        for(int i=,ls=;i<=n;i++)

        {

            mp[i].h=mp[i-].h+ls;

            if(ss[i]=='_')ls=,mp[i].kind=;

            else if(ss[i]=='/')ls=,mp[i].kind=;

            else if(ss[i]=='\\')ls=,mp[i].kind=,mp[i].h--;

            //printf("%d : %d\n",i,mp[i].h);

        }

        build(,,n);

        for(int i=,mi=query(,,m);i<=m;i++)

            sum+=get_ans(i,mi);

        ans=sum;

        for(int i=m+,ls=query(,,m);i<=n;i++)

        {

            int mi=query(,i-m+,i);

            sum-=get_ans(i-m,ls);

            sum+=get_ans(i,mi);

            if(ls>mi)

                sum+=(m-1.0)*(ls-mi);

            else if(ls<mi)

                sum-=(mi-ls)*(m-1.0);

            ls=mi;

            ans=min(sum,ans);

        }

        printf("Case #%d: %.1f\n",cs++,ans);

    }

    return ;

}