# include <bits/stdc++.h>
using namespace std;

const int N = 1e5+7;

/***************************************/

int n,m;
int c[N];
vector<int >G[N];

int fa[N],sz[N],son[N],dep[N];

int dfs1(int u,int f,int d){
    fa[u]=f,sz[u]=1,son[u]=0,dep[u]=d;
    int gz = G[u].size();
    for(int to,i=0;i<gz;i++){
        to = G[u][i];
        if(to==f) continue;
        dfs1(to,u,d+1);
        sz[u]+=sz[to];
        if(sz[son[u]]<sz[to]) son[u]=to;
    }
}

int top[N],tree[N],pre[N],cnt;

int dfs2(int u,int tp){
    top[u]=tp,tree[u]=++cnt,pre[tree[u]]=u;
    if(son[u]) dfs2(son[u],tp);
    int gz = G[u].size();
    for(int to,i=0;i<gz;i++){
        to = G[u][i];
        if(to==fa[u]||to==son[u])continue;
        dfs2(to,to);
    }
}

int sum[N<<2],lazy[N<<2],lc[N<<2],rc[N<<2];

void pushup(int rt){
    sum[rt] = sum[rt<<1]+sum[rt<<1|1]-(rc[rt<<1] == lc[rt<<1|1]);
    lc[rt]=lc[rt<<1],rc[rt]=rc[rt<<1|1];
}

void pushdown(int rt){
    if(lazy[rt]!=-1){
        lazy[rt<<1] = lazy[rt<<1|1] = lazy[rt];
        sum [rt<<1] = sum [rt<<1|1] = 1;
        lc[rt<<1]   = rc[rt<<1]   = lazy[rt];
        lc[rt<<1|1] = rc[rt<<1|1] = lazy[rt];
        lazy[rt]=-1;
    }
}

void build(int rt,int l,int r){
    if(l==r){
        sum[rt]=1,rc[rt]=lc[rt]=c[pre[l]];
        return ;
    }
    int m = (r+l)>>1;
    build(rt<<1  ,l  ,m);
    build(rt<<1|1,m+1,r);
    pushup(rt);
}

void update(int rt,int l,int r,int L,int R,int clr){
    if(L<=l&&r<=R){
        rc[rt]=lc[rt]=lazy[rt]=clr;
        sum[rt] = 1;
        return ;
    }
    pushdown(rt);
    int m = (r+l)>>1;
    if(L<=m) update(rt<<1  ,l  ,m,L,R,clr);
    if(R> m) update(rt<<1|1,m+1,r,L,R,clr);
    pushup(rt);
    return ;
}

int query(int rt,int l,int r,int L,int R){
    if(L>R) return 0;
    if(L<=l&&r<=R) return sum[rt];
    pushdown(rt);
    int ans = 0,m = (r+l)>>1;
    if(R<=m)      ans = query(rt<<1  ,l,  m,L,R);
    else if(L>m)  ans = query(rt<<1|1,m+1,r,L,R);
    else          ans = query(rt<<1  ,l,  m,L,R)+
                        query(rt<<1|1,m+1,r,L,R)-
                        (rc[rt<<1]==lc[rt<<1|1]);
    pushup(rt);
    return ans;
}

int query_color(int rt,int l,int r,int pos){
    if(l==r)  return lc[rt];
    pushdown(rt);
    int m = (r+l)>>1,ans;
    if(pos<=m) ans = query_color(rt<<1  ,l  ,m,pos);
    else       ans = query_color(rt<<1|1,m+1,r,pos);
    pushup(rt);
    return ans;
}

void init(){
    cnt = 0;
    for(int i=1;i<=n;i++)G[i].clear();
    memset(sum,0,sizeof(sum));
    memset(lazy,-1,sizeof(lazy));
};

void brush(int x,int y,int clr){
    int fx = top[x],fy = top[y];
    while(fx!=fy){
        if(dep[fx]<dep[fy]) swap(fx,fy),swap(x,y);
        update(1,1,n,tree[fx],tree[x],clr);
        x = fa[fx],fx = top[x];
    }
    if(tree[x]>tree[y]) swap(x,y);
    update(1,1,n,tree[x],tree[y],clr);
    return ;
}

void solve(int x,int y){
    int fx = top[x],fy = top[y];
    int ans = 0;
    while(fx!=fy){
        if(dep[fx]<dep[fy]) swap(fx,fy),swap(x,y);
        ans += query(1,1,n,tree[fx],tree[x]);
        if(query_color(1,1,n,tree[fa[fx]]) == query_color(1,1,n,tree[fx])) ans--;
        x = fa[fx],fx = top[x];
    }
    if(tree[x]>tree[y]) swap(x,y);
    ans += query(1,1,n,tree[x],tree[y]);
    printf("%d\n",ans);
    return ;
}

int main(){
    while(~scanf("%d%d",&n,&m)){
        init();

        for(int i=1;i<=n;i++) scanf("%d",&c[i]);

        for(int i=2,u,v;i<=n;i++){
            scanf("%d %d",&u,&v);
            G[u].push_back(v);
            G[v].push_back(u);
        }

        dfs1(1,-1,1);
        dfs2(1,1);
        build(1,1,n);

        int l,r,x;
        char a[10];
        while(m--){
            scanf("%s",a);
            scanf("%d %d",&l,&r);
            if(a[0]=='C'){
                scanf("%d",&x);
                brush(l,r,x);
            }
            else  solve(l,r);
        }
    }
    return 0;
}