#include <cstdio>

#include <cstring>

#include <iostream>

#define N 400001

#define ls now << 1

#define rs now << 1 | 1

#define swap(x, y) ((x) ^= (y) ^= (x) ^= (y))

#define pushup(now) Lcol[now] = Lcol[ls], Rcol[now] = Rcol[rs], col[now] = col[ls] + col[rs] - (Rcol[ls] == Lcol[rs])

int n, m, cnt, tim;

int head[N], to[N << 1], next[N << 1];

int a[N], f[N], deep[N], size[N], son[N], tid[N], top[N], rank[N], L[N], R[N], Lcol[N], Rcol[N], col[N], laz[N];

inline int read()

{

	int x = 0, f = 1;

	char ch = getchar();

	for(; !isdigit(ch); ch = getchar()) if(ch == '-') f = -1;

	for(; isdigit(ch); ch = getchar()) x = (x << 1) + (x << 3) + ch - '0';

	return x * f;

}

inline void add(int x, int y)

{

	to[cnt] = y;

	next[cnt] = head[x];

	head[x] = cnt++;

}

inline void dfs1(int u)

{

	int i, v;

	size[u] = 1;

	deep[u] = deep[f[u]] + 1;

	for(i = head[u]; i ^ -1; i = next[i])

	{

		v = to[i];

		if(v ^ f[u])

		{

			f[v] = u;

			dfs1(v);

			size[u] += size[v];

			if(son[u] == -1 || size[son[u]] < size[v]) son[u] = v;

		}

	}

}

inline void dfs2(int u, int t)

{

	int i, v;

	top[u] = t;

	tid[u] = ++tim;

	rank[tim] = u;

	if(son[u] == -1) return;

	dfs2(son[u], t);

	for(i = head[u]; i ^ -1; i = next[i])

	{

		v = to[i];

		if(v ^ f[u] && v ^ son[u]) dfs2(v, v);

	}

}

inline void build(int now, int l, int r)

{

	L[now] = l;

	R[now] = r;

	if(l == r)

	{

		col[now] = 1;

		Lcol[now] = Rcol[now] = a[rank[l]];

		return;

	}

	int mid = (l + r) >> 1;

	build(ls, l, mid);

	build(rs, mid + 1, r);

	pushup(now);

}

inline void pushdown(int now)

{

	if(laz[now])

	{

		col[ls] = col[rs] = 1;

		laz[ls] = laz[rs] = Lcol[ls] = Lcol[rs] = Rcol[ls] = Rcol[rs] = laz[now];

		laz[now] = 0;

	}

}

inline void update(int now, int l, int r, int z)

{

	if(l <= L[now] && R[now] <= r)

	{

		col[now] = 1;

		laz[now] = Lcol[now] = Rcol[now] = z;

		return;

	}

	pushdown(now);

	int mid = (L[now] + R[now]) >> 1;

	if(l <= mid) update(ls, l, r, z);

	if(mid < r) update(rs, l, r, z);

	pushup(now);

}

inline void q_update(int u, int v, int z)

{

	while(top[u] ^ top[v])

	{

		if(deep[top[u]] < deep[top[v]]) swap(u, v);

		update(1, tid[top[u]], tid[u], z);

		u = f[top[u]];

	}

	if(deep[u] > deep[v]) swap(u, v);

	update(1, tid[u], tid[v], z);

}

inline int q_color(int now, int x)

{

	if(L[now] == R[now]) return Lcol[now];

	pushdown(now);

	int mid = (L[now] + R[now]) >> 1;

	if(x <= mid) return q_color(ls, x);

	else return q_color(rs, x);

}

inline int query(int now, int l, int r)

{

	if(l <= L[now] && R[now] <= r) return col[now];

	pushdown(now);

	int mid = (L[now] + R[now]) >> 1, ans = 0;

	if(l <= mid) ans += query(ls, l, r);

	if(mid < r) ans += query(rs, l, r);

	if(l <= mid && mid < r) ans -= (Rcol[ls] == Lcol[rs]);

	return ans;

}

inline int q_query(int u, int v)

{

	int ans = 0;

	while(top[u] ^ top[v])

	{

		if(deep[top[u]] < deep[top[v]]) swap(u, v);

		ans += query(1, tid[top[u]], tid[u]);

		ans -= (q_color(1, tid[f[top[u]]]) == q_color(1, tid[top[u]]));

		u = f[top[u]];

	}

	if(deep[u] > deep[v]) swap(u, v);

	ans += query(1, tid[u], tid[v]);

	return ans;

}

int main()

{

	int i, x, y, z;

	char s[10];

	n = read();

	m = read();

	memset(son, -1, sizeof(son));

	memset(head, -1, sizeof(head));

	for(i = 1; i <= n; i++) a[i] = read();

	for(i = 1; i < n; i++)

	{

		x = read();

		y = read();

		add(x, y);

		add(y, x);

	}

	dfs1(1);

	dfs2(1, 1);

	build(1, 1, n);

	for(i = 1; i <= m; i++)

	{

		scanf("%s", s);

		x = read();

		y = read();

		if(s[0] == 'C')

		{

			z = read();

			q_update(x, y, z);

		}

		else printf("%d\n", q_query(x, y));

	}

	return 0;

}