#include<bits/stdc++.h>
#define For(i,a,b) for(int i=(a);i<=(b);++i)
#define Rep(i,a,b) for(int i=(a);i>=(b);--i)
#define ll long long
using namespace std;
inline int read()
{
    char c=getchar();int x=0;bool f=0;
    for(;!isdigit(c);c=getchar())f^=!(c^45);
    for(;isdigit(c);c=getchar())x=(x<<1)+(x<<3)+(c^48);
    if(f)x=-x;return x;
}

#define fi first
#define se second
#define pb push_back
#define mkp make_pair
typedef pair<int,int>pii;
typedef vector<int>vi;

#define maxn 300005
#define inf 0x3f3f3f3f

int n,m;
char s[maxn];
vi e[maxn];

int fa[maxn],dep[maxn],sz[maxn];
int dfn[maxn],que[maxn],out[maxn],idx;
int st[20][maxn],lg[maxn];
int depmin(int u,int v){return dep[u]<dep[v]?u:v;}
void dfs(int u){
	dfn[u]=++idx,que[idx]=u,sz[u]=1;
	for(auto v:e[u]){
		if(v==fa[u])continue;
		fa[v]=u,dep[v]=dep[u]+1;
		dfs(v),sz[u]+=sz[v];
	}out[u]=idx;
}
void init(){
	dfs(1);
	For(i,2,n)st[0][i]=fa[que[i]],lg[i]=lg[i>>1]+1;
	For(j,1,19)
		For(i,1,n-(1<<j)+1)
			st[j][i]=depmin(st[j-1][i],st[j-1][i+(1<<(j-1))]);
}
int lca(int u,int v){
	if(u==v)return u;
	if((u=dfn[u])>(v=dfn[v]))swap(u,v); ++u;
	int k=lg[v-u+1];
	return depmin(st[k][u],st[k][v-(1<<k)+1]);
}
int dist(int u,int v){
	if(!u||!v)return -((!u)+(!v));
	return dep[u]+dep[v]-2*dep[lca(u,v)];
}
bool dfncmp(int u,int v){
	return dfn[u]<dfn[v]; 
}

int qu[maxn]; char qc[maxn];
int f[maxn],g[maxn];
ll sum;
bool is1(char c){return c=='C'||c=='?';}
bool is0(char c){return c=='A'||c=='?';}
void predp(int u,int c=0){
	f[u]=is1(s[u]);
	c+=is0(s[u]);
	for(int v:e[u])predp(v,c),f[u]+=f[v];
	g[u]=f[u]-c;
}

int B;
/*
询问分块，虚树 
每次:
加一条祖先链的 f,g 
加 子树的 g 
f easy
max(g,0) 对虚树上每个部分暴力修改 
*/

// B = 500 个询问一块 

int *c[4005],ccc[4005][4005],c0[4005],cg[4005];
void inic(){
	For(i,0,4004) c[i]=ccc[i]+2002;
}

int p[maxn],len;
int vfa[maxn];
vi G[maxn];
int in[maxn],up[maxn],dw[maxn],bel[maxn];

void ins(int id,int u){
	bel[u]=id;
	if(s[u]=='A')++c0[id];
	else if(s[u]=='?'){
		if(g[u]>0) ++cg[id];
		if(g[u]>=-B && g[u]<=B) ++c[id][g[u]];
	}
}

// f+=1,g+=1,g-=1
int tagf[maxn],tagg[maxn];
void addf(int u,int w){
	tagf[u]+=w;
	sum+=w*c0[u];
//	cout<<"addf "<<u<<" "<<w<<endl;
}
void addg(int u){
	cg[u]+=c[u][-tagg[u]];
	++tagg[u];
	sum+=cg[u];
}
void subg(int u){
	--tagg[u];
	sum-=cg[u];
	cg[u]-=c[u][-tagg[u]];
}
void addg(int u,int op){
//	cout<<"addg "<<u<<" "<<op<<endl;
	if(op==1) addg(u);
	else subg(u);
}

void MDF(int u,char ch,int op){
//	cout<<"u: "<<u<<" "<<f[u]<<" "<<g[u]<<" "<<s[u]<<'\n';
	if(ch=='C') f[u]+=op,g[u]+=op;
	if(ch=='A') sum+=f[u]*op,g[u]-=op;
	if(ch=='?') sum+=max(g[u],0)*op,f[u]+=op;
}

void mdfanc(int u,int op){
//	cout<<"mdfanc "<<u<<" "<<op<<endl;
	int x=u;
	while(x){
		addf(in[x],op);
		addg(in[x],op);
		x=vfa[x];
		if(!x)break;
		if(s[x]=='?') sum-=max(g[x],0);
		if(s[x]=='A') sum+=op;
		f[x]+=op,g[x]+=op;
		if(s[x]=='?') sum+=max(g[x],0);
	}
}

int Q[maxn],hd,tl;
void mdfsub(int u,int op){
//	cout<<"mdfsub "<<u<<" "<<op<<endl;
	Q[hd=tl=1]=u;
	while(hd<=tl){
		int x=Q[hd++];
		if(x!=u){
			addg(in[x],-op);
			if(s[x]=='?') sum-=max(0,g[x]);
			g[x]-=op;
			if(s[x]=='?') sum+=max(0,g[x]);
		}
		addg(in[x]+len,-op);
		for(int v:G[x])
			Q[++tl]=v;
	}
}

void mdf(int u,char c){
	if(s[u]==c)return;
	
	MDF(u,s[u],-1);
	MDF(u,c,1);
	char lst=s[u];
	
//	cout<<"Sum "<<sum<<endl;
	if(is1(lst) && !is1(c)) mdfanc(u,-1);
	if(!is1(lst) && is1(c)) mdfanc(u,1);
//	cout<<"nowsum "<<sum<<endl;
	if(is0(lst) && !is0(c)) mdfsub(u,-1);
	if(!is0(lst) && is0(c)) mdfsub(u,1);
	
	s[u]=c;
}

void solve(int l,int r)
{
//	cout<<"solve "<<l<<" "<<r<<endl;
	len=0;
	For(i,l,r)p[++len]=qu[i]; p[++len]=1;
	sort(p+1,p+len+1,dfncmp);
	Rep(i,len-1,1)p[++len]=lca(p[i],p[i+1]);
	sort(p+1,p+len+1,dfncmp);
	len=unique(p+1,p+len+1)-p-1;
	For(i,1,len)G[p[i]].clear();
	For(i,2,len){
		vfa[p[i]]=lca(p[i-1],p[i]);
		G[vfa[p[i]]].pb(p[i]);
	}
	For(i,1,len){
		int u=p[i];
		in[u]=i;
		int x=u;
		while(x!=vfa[u]) dw[x]=u,x=fa[x];
	}
	For(i,1,n)
		up[i]=in[i]?i:up[fa[i]];
	For(i,1,n)
		if(!in[i]){
			if(dw[i])ins(in[dw[i]],i);
			else ins(in[up[i]]+len,i);
		}
	For(i,l,r){
		mdf(qu[i],qc[i]);
		printf("%lld\n",sum);
	}
	// clear
	For(i,1,n){
		if(!in[i]) f[i]+=tagf[bel[i]],g[i]+=tagg[bel[i]];
		in[i]=bel[i]=dw[i]=up[i]=vfa[i]=0;
	}
	For(i,1,2*len){
		tagf[i]=tagg[i]=0;
		c0[i]=cg[i]=0;
		For(j,-B,B)c[i][j]=0;
	}
}

signed main()
{
	//freopen("partial.in","r",stdin);
	//freopen("partial.out","w",stdout);
	n=read(),m=read();
	scanf("%s",s+1);
	For(i,2,n)fa[i]=read(),e[fa[i]].pb(i);
	init();
	predp(1);
	For(i,1,n)
		if(s[i]=='A') sum+=f[i];
		else if(s[i]=='?') sum+=max(0,g[i]);
	For(i,1,m)qu[i]=read(),cin>>qc[i];
	B=sqrt(m);
	inic();
	for(int l=1,r;l<=m;l=r+1){
		r=min(m,l+B-1);
		solve(l,r);
	}
	return 0;
}