#include <bits/stdc++.h>
#define pb push_back 
#define ott(i,l,r) for (int i = l; i <= r; i ++)
#define tto(i,l,r) for (int i = r; i >= l; i --)
using namespace std;
using ll = long long;
int read () {
	int x = 0; bool f = 0; char c = getchar ();
	while (!isdigit (c)) f |= (c == '-'), c = getchar ();
	while (isdigit (c)) x = (x << 3) + (x << 1) + (c ^ 48), c = getchar ();
	if (f) x = -x; return x;
}
const int N = 3e5 + 110;
int n, q, res;
vector <int> e[N];
int fa[N];
int up[N], dn[N];
char s[N];
void dfs (int u) {
	dn[u] = 0;
	for (int v : e[u]) {
		up[v] = up[u] + (s[u] != 'C');
		dfs (v);
		dn[u] += dn[v] + (s[v] != 'A');
	}
	if (s[u] == 'A') res += dn[u];
	if (s[u] == '?') res += max (0, dn[u] - up[u]);
	return ;
}
void cup (int u, int val) {
	for (int v : e[u]) {
		if (s[v] == '?') res -= max (0, dn[v] - up[v]);
		up[v] += val;
		if (s[v] == '?') res += max (0, dn[v] - up[v]);
		cup (v, val);
	}
	return ;
}
void cdn (int u, int val) {
	if (!u) return ;
	if (s[u] == 'A') res += val;
	if (s[u] == '?') res -= max (0, dn[u] - up[u]);
	dn[u] += val;
	if (s[u] == '?') res += max (0, dn[u] - up[u]);
	cdn (fa[u], val);
	return ;
}

int main () {
	n = read (), q = read (), cin >> s + 1; ott (i, 2, n) e[fa[i] = read ()].pb (i);
	dfs (1); while (q --) {
		int x = read (); char c = getchar ();
		if (s[x] != 'C') cup (x, -1); if (s[x] != 'A') cdn (fa[x], -1);
		s[x] = c;
		if (s[x] != 'C') cup (x, 1); if (s[x] != 'A') cdn (fa[x], 1);
		printf ("%d\n", res);
	}
	return 0;
}