//============================================================================// Name        : D.cpp// Author      : L_Ecry// Version     :// Copyright   : Your copyright notice// Description : Hello World in C++, Ansi-style//============================================================================#include<cstdio>#include<cstring>#include<algorithm>#include<cmath>#include <iostream>#define N 50050using namespace std;int value[N*4];char s[N];inline int cal(int l,int r,int mid){    int res=0;    if(mid>l&&s[mid-1]==‘w‘&&s[mid]==‘b‘&&s[mid+1]==‘w‘)res++;    if(mid+1<r&&s[mid]==‘w‘&&s[mid+1]==‘b‘&&s[mid+2]==‘w‘)res++;    return res;}void build(int l,int r,int i){    if(l==r)    {        value[i]=0;        return ;    }    int mid=(l+r)>>1;    int lson=(i<<1),rson=(i<<1|1);    build(l,mid,lson);    build(mid+1,r,rson);    value[i]=value[lson]+value[rson]+cal(l,r,mid);}void update(int l,int r,int p,int i){    if(l==r)    {        return;    }    int mid=(l+r)>>1;    int lson=(i<<1),rson=(i<<1|1);    if(p<=mid)update(l,mid,p,lson);    else update(mid+1,r,p,rson);    value[i]=value[lson]+value[rson]+cal(l,r,mid);}int query(int l,int r,int pl,int pr,int i){    if(l==pl&&r==pr)    {        return value[i];    }    int mid=(l+r)>>1;    if(pr<=mid)return query(l,mid,pl,pr,i<<1);    else if(pl>mid)return query(mid+1,r,pl,pr,i<<1|1);    else    {        return query(l,mid,pl,mid,i<<1)+query(mid+1,r,mid+1,pr,i<<1|1)+cal(pl,pr,mid);    }}int n,m;void init(){    scanf("%d%d",&n,&m);    scanf(" %s",s+1);    build(1,n,1);}void solve(){    while(m--)    {        int x,y,z;        char c;        scanf("%d%d",&x,&y);        if(x==0)        {            scanf("%d",&z);            y++;z++;            printf("%d\n",query(1,n,y,z,1));        }        else        {            scanf(" %c",&c);            y++;            s[y]=c;            update(1,n,y,1);        }    }}int main() {    int tt,ri=0;    scanf("%d",&tt);    while(tt--)    {        init();        printf("Case %d:\n",++ri);        solve();    }    return 0;}