#include<bits/stdc++.h>
#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 () {
	bool f = false; char c = getchar (); int x = 0;
	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 + 5, B = 600;
struct OPT {
	int x; 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, idx, m, sc;
int fa[N], ssp[N], sspd[N], f0[N], f1[N], dfn[N][2], dfu[N], bl[N], cp[7 * B * B], bu[B + 1][B + 1], sl[B];
struct BIT {
	int a[N];
	void add (int x, int y) {for (; x < n; x |= x + 1) a[x] += y;}
	int ask (int x, int ss = 0) {for (; x --; x &= x + 1) ss += a[x]; return ss;}
};
struct FUCK {
	BIT a, b;
	ll ans;
	void init () {ott (i, 0, n - 1) 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.ask (dfn[x][1]) - a.ask (dfn[x][0] + 1) - b.ask (dfn[x][0])) * y;
	}
	ll query () {return ans;}
} t0;
vector <int> e[N];
set <pair <int, int>> st;
ll ans; char ch[N];
bool sp[N], spd[N], vi[N];
void dfs (int u) {
	dfu[dfn[u][0] = idx ++] = u;
	for (int v : e[u]) dfs (v);
	dfn[u][1] = idx;
	return ;
}
void build () {
	ott (i, 0, n - 1) ssp[i + 1] = ssp[i] + sp[i], sspd[i + 1] = sspd[i] + spd[i], f0[i] = ch[i] != 'A', f1[i] = ch[i] != 'C';
	tto (i, 1, n) f0[fa[i]] += f0[i];
	ott (i, 1, n - 1) f1[i] += f1[fa[i]];
	ans = 0;
	ott (i, 0, n - 1) {
		f0[i] -= f1[i];
		if (ch[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));
	m = sc = 0;
	ott (i, 0, n - 1) {
		if (sp[i]) {
			vi[sl[sc ++] = 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] = m] = {dfn[i][0], dfn[i][1], cp + (m << 1 | 1) * B}, ++ m;
			if (ch[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) {
			ott (j, k, it -> first - 1) {
				int v = dfu[j];
				if (vi[v])continue;
				if (!~u) {
					b[u = m] = {dfn[v][0], dfn[v][1], cp + (m << 1 | 1) * B};
					++ m;
				}
				if (ch[v] == '?') b[u].add (f0[v]);
			}
			k = it -> second, it = st.erase (it);
		}
		ott (j, k, r - 1) {
			int v = dfu[j];
			if (vi[v])continue;
			if (!~u) {
				b[u = m] = {dfn[v][0], dfn[v][1], cp + (m << 1 | 1) * B};
				++ m;
			}
			if (ch[v] == '?') b[u].add (f0[v]);
		}
		st.emplace (l, r);
	}
	ott (i, 0, m - 1) 
	    for (int j = B; -- j > -B;) 
			b[i].c[j] += b[i].c[j + 1];
	return ;
}
int main () {
	//freopen ("data.in", "r", stdin); freopen ("res.out", "w", stdout);
	n = read (), q = read (), scanf ("%s", ch); ott (i, 1, n - 1) e[-- (fa[i] = read ())].emplace_back (i);
	dfs (0); ott (i, 0, q - 1) -- (o[i].x = read ()), scanf (" %c", &o[i].c);
	t0.init ();
	ott (i, 0, n - 1) if (ch[i] == 'A') t0.update (i, 1);
	for (int ql = 0, qr; ql < q; ql = qr + 1) {
		qr = min (ql + B, q) - 1;
		ott (i, ql, qr) spd[dfn[o[i].x][0]] = true, sp[o[i].x] = true;
		build ();
		ott (i, ql, qr) {
			if(ch[o[i].x] != o[i].c)
			{
				int a0 = (o[i].c == 'C') - (ch[o[i].x] == 'C'), aa0 = -min (a0, 0);
				int a1 = (o[i].c != 'A') - (ch[o[i].x] != 'A'), aa1 = -min (a1 ,0);
				int *dd = dfn[o[i].x];
				if (a0)
				    ott (j, ssp[o[i].x], sc - 1) {
						int u = sl[j];
						if (dd[0] <= dfn[u][0] && dfn[u][1] <= dd[1]) {
						if (f0[u] >= aa0 && ch[u] == '?') ans += a0;
						f0[u] += a0;
					}
				}
				if (a1)
					ott (j, 0, ssp[o[i].x]) {
						int u = sl[j];
						if (dfn[u][0] <= dd[0] && dd[1] <= dfn[u][1]) {
							if (f0[u] >= aa1 && ch[u] == '?') ans += a1;
							f0[u] += a1;
						}
					}
				ott (j, 0, m - 1) {
					if (dd[0] <= b[j].dl && b[j].dr <= dd[1]) {
						if (a0 == 1) ans += *b[j].c --;
						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 --;
						if (a1 == -1) ans -= *++ b[j].c;
					}
				}
				if (ch[o[i].x] == '?') ans -= max (f0[o[i].x], 0);
				if (o[i].c == '?') ans += max (f0[o[i].x], 0);
				t0.update (o[i].x, (o[i].c == 'A') - (ch[o[i].x] == 'A')), ch[o[i].x] = o[i].c;
			}
			printf ("%lld\n", ans + t0.ans);
		}
		ott (i, ql, qr) spd[dfn[o[i].x][0]] = false, sp[o[i].x] = false;
	}
	return 0;
}