// created:  2024-08-30 15:50:03
#include<cstdio>
#include<cctype>
#include<cstring>
#include<algorithm>
#include<set>
#include<vector>
#define F(i,l,r) for(int i=(l),i##_end=(r);i<i##_end;++i)
#define I128 //||is_same<T,__int128_t>::value||is_same<T,__uint128_t>::value
using namespace std;
template<typename T>enable_if_t<is_integral<T>::value I128,void> readmain(T &x)
{
	bool neg=false;int c=getchar();
	for(;!isdigit(c);c=getchar())if(c=='-')neg=true;
	for(x=0;isdigit(c);c=getchar())x=(T)(10*x+(c-'0'));
	if(neg)x=-x;
}
template<typename T>T& read(T &x){readmain(x);return x;}
template<typename T,typename ...Tr>void read(T &x,Tr&... r){readmain(x);read(r...);}
typedef long long ll;
constexpr int N=3e5+5,B=600;
struct operation
{
	int p;char c;
}o[N];
struct block
{
	int dl,dr,*c;
	void add(int x)
	{
		if(x<-(B-1))return;
		x=min(x,B);
		++c[x];
	}
}b[3*N];
int n,q,fa[N],ssp[N],sspd[N],f0[N],f1[N],dfn[N][2],idfn[N],dind,bl[N],cp[7*B*B],bb,bu[B+1][B+1],sl[B],sc;
namespace s0
{
	struct fw
	{
		int a[N];
		void add(int x,int y){for(;x<n;x|=x+1)a[x]+=y;}
		int sum(int x,int ans=0){for(;x--;x&=x+1)ans+=a[x];return ans;}
	}a,b;
	ll ans;
	void init(){F(i,0,n)a.a[i]=(i+1)&~i;}
	void update(int x,int y)
	{
		if(!y)return;
		a.add(dfn[x][0],-y);
		b.add(dfn[x][0],y);
		b.add(dfn[x][1]-1,-y);
		ans+=(a.sum(dfn[x][1])-a.sum(dfn[x][0]+1)-b.sum(dfn[x][0]))*y;
	}
	ll query(){return ans;}
}
vector<int> ch[N];
set<pair<int,int>> st;
ll ans;
bool sp[N],spd[N],vi[N];
char s[N];
void dfs(int u)
{
	idfn[dfn[u][0]=dind++]=u;
	for(int v:ch[u])dfs(v);
	dfn[u][1]=dind;
}
void build()
{
	F(i,0,n)ssp[i+1]=ssp[i]+sp[i],sspd[i+1]=sspd[i]+spd[i],f0[i]=s[i]!='A',f1[i]=s[i]!='C';
	for(int i=n;--i;)f0[fa[i]]+=f0[i];
	F(i,1,n)f1[i]+=f1[fa[i]];
	ans=0;
	F(i,0,n)
	{
		f0[i]-=f1[i];
		if(s[i]=='?')ans+=max(f0[i],0);
	}
	memset(bu,0xff,sizeof bu);
	memset(vi,0,sizeof(bool)*n);
	memset(cp,0,sizeof(int)*2*B*(3*B+1));
	bb=0;
	sc=0;
	F(i,0,n)
	{
		if(sp[i])
		{
			sl[sc++]=i;
			vi[i]=true;
			continue;
		}
		int dl=sspd[dfn[i][0]],dr=sspd[dfn[i][1]];
		if(dl!=dr)
		{
			if(!~bu[dl][dr])b[bu[dl][dr]=bb]={dfn[i][0],dfn[i][1],cp+(2*bb+1)*B},++bb;
			if(s[i]=='?')b[bu[dl][dr]].add(f0[i]);
			vi[i]=true;
		}
	}
	st.clear();
	for(int i=sc;--i>=-1;)
	{
		int l=~i?dfn[sl[i]][0]:0,r=~i?dfn[sl[i]][1]:n,k=l;
		set<pair<int,int>>::iterator it=st.lower_bound({l,0});
		int u=-1;
		while(it!=st.end()&&it->first<r)
		{
			F(j,k,it->first)
			{
				int v=idfn[j];
				if(vi[v])continue;
				if(!~u)
				{
					b[u=bb]={dfn[v][0],dfn[v][1],cp+(2*bb+1)*B};
					++bb;
				}
				if(s[v]=='?')b[u].add(f0[v]);
			}
			k=it->second;
			it=st.erase(it);
		}
		F(j,k,r)
		{
			int v=idfn[j];
			if(vi[v])continue;
			if(!~u)
			{
				b[u=bb]={dfn[v][0],dfn[v][1],cp+(2*bb+1)*B};
				++bb;
			}
			if(s[v]=='?')b[u].add(f0[v]);
		}
		st.emplace(l,r);
	}
	F(i,0,bb)for(int j=B;--j>-B;)b[i].c[j]+=b[i].c[j+1];
}
int main()
{
	read(n,q);
	scanf("%s",s);
	F(i,1,n)ch[--read(fa[i])].emplace_back(i);
	dfs(0);
	F(i,0,q)--read(o[i].p),scanf(" %c",&o[i].c);
	s0::init();
	F(i,0,n)if(s[i]=='A')s0::update(i,1);
	for(int ql=0,qr;ql<q;ql=qr)
	{
		qr=min(ql+B,q);
		F(i,ql,qr)spd[dfn[o[i].p][0]]=true,sp[o[i].p]=true;
		build();
		F(i,ql,qr)
		{
			if(s[o[i].p]!=o[i].c)
			{
				int a0=(o[i].c=='C')-(s[o[i].p]=='C'),aa0=-min(a0,0);
				int a1=(o[i].c!='A')-(s[o[i].p]!='A'),aa1=-min(a1,0);
				int *dd=dfn[o[i].p];
				if(a0)F(j,ssp[o[i].p],sc)
				{
					int u=sl[j];
					if(dd[0]<=dfn[u][0]&&dfn[u][1]<=dd[1])
					{
						if(f0[u]>=aa0&&s[u]=='?')ans+=a0;
						f0[u]+=a0;
					}
				}
				if(a1)F(j,0,ssp[o[i].p]+1)
				{
					int u=sl[j];
					if(dfn[u][0]<=dd[0]&&dd[1]<=dfn[u][1])
					{
						if(f0[u]>=aa1&&s[u]=='?')ans+=a1;
						f0[u]+=a1;
					}
				}
				F(j,0,bb)
				{
					if(dd[0]<=b[j].dl&&b[j].dr<=dd[1])
					{
						if(a0==1)ans+=*b[j].c--;
						else if(a0==-1)ans-=*++b[j].c;
					}
					if(b[j].dl<=dd[0]&&dd[1]<=b[j].dr)
					{
						if(a1==1)ans+=*b[j].c--;
						else if(a1==-1)ans-=*++b[j].c;
					}
				}
				if(s[o[i].p]=='?')ans-=max(f0[o[i].p],0);
				if(o[i].c=='?')ans+=max(f0[o[i].p],0);
				s0::update(o[i].p,(o[i].c=='A')-(s[o[i].p]=='A'));
				s[o[i].p]=o[i].c;
			}
			printf("%lld\n",ans+s0::query());
		}
		F(i,ql,qr)spd[dfn[o[i].p][0]]=false,sp[o[i].p]=false;
	}
	return 0;
}