#include <bits/stdc++.h>
using namespace std;
const int N=100000;
#define re register
#define lc (p<<1)
#define rc (p<<1|1)

inline int rd(){
    char c=getchar();
    int v=0,f=1;
    while(c<'0'||c>'9') {
        if(c=='-') f=-1;
        c=getchar();
    }
    while(c>='0'&&c<='9') v=(v<<3)+(v<<1)+(c^48),c=getchar();
    return v*f;
}

struct node{
    int u,v,w,nxt;
}e[N<<1];
int first[N],last;
inline void add(re int u,re int v,re int w){
    e[++last].u=u,e[last].v=v,e[last].w=w;
    e[last].nxt=first[u];
    first[u]=last;
}

int st[N],siz[N],hson[N],top[N],pre[N],fa[N],dep[N],tot,a[N];
void dfs(re int u,re int faa){
    siz[u]=1;
    fa[u]=faa;
    hson[u]=0;
    for(int i=first[u];i;i=e[i].nxt){
        int v=e[i].v;
        if(v==fa[u]) continue;
        dep[v]=dep[u]+1;
        dfs(v,u);
        siz[u]+=siz[v];
        if(siz[v]>siz[hson[u]]) hson[u]=v;
    }
    return;
}
void _dfs(re int u,re int tp){
    st[u]=++tot;
    pre[tot]=u;
    top[u]=tp;
    if(hson[u]) _dfs(hson[u],tp);
    for(int i=first[u];i;i=e[i].nxt)
        if(e[i].v!=fa[u]&&hson[u]!=e[i].v)
            _dfs(e[i].v,e[i].v);
    return;
}

struct tree{
    int l,r,lcol,rcol,sum,lazy;
    tree(){l=r=lcol=rcol=sum=lazy=0;}
}t[N<<2];
inline void pushup(re int p){
    t[p].lcol=t[lc].lcol;
    t[p].rcol=t[rc].rcol;
    t[p].sum=t[lc].sum+t[rc].sum-(t[lc].rcol==t[rc].lcol);
}
inline void pushnow(re int p,re int v){
    t[p].lcol=t[p].rcol=v;
    t[p].lazy=v;
    t[p].sum=1;
}
inline void pushdown(re int p){
    if(t[p].lazy){
        pushnow(lc,t[p].lazy);
        pushnow(rc,t[p].lazy);
        t[p].lazy=0;
    }
}
void build(re int p,re int l,re int r){
    t[p].l=l,t[p].r=r;
    if(l==r) {
        t[p].lcol=t[p].rcol=a[pre[l]];
        t[p].sum=1;
        t[p].lazy=0;
        return;
    }
    re int mid=l+r>>1;
    build(lc,l,mid);
    build(rc,mid+1,r);
    pushup(p);
    return ;
}
void change(re int p,re int ql,re int qr,re int v){
    if(t[p].l>=ql&&t[p].r<=qr){
        pushnow(p,v);
        return;
    }
    pushdown(p);
    re int mid=t[p].l+t[p].r>>1;
    if(ql<=mid) change(lc,ql,qr,v);
    if(qr>mid) change(rc,ql,qr,v);
    pushup(p);
    return;
}
tree query(re int p,re int ql,re int qr){
    if(t[p].l>=ql&&t[p].r<=qr){
        return t[p];
    }
    pushdown(p);
    re int mid=t[p].l+t[p].r>>1;
    re tree ll,rr;
    if(ql<=mid) ll=query(lc,ql,qr);
    if(qr>mid) rr=query(rc,ql,qr);
    re tree ans;
    ans.sum+=ll.sum+rr.sum-(ll.rcol==rr.lcol);
    ans.rcol=rr.rcol?rr.rcol:ll.rcol;
    ans.lcol=ll.lcol?ll.lcol:rr.lcol;
    return ans;
}
void change(re int x,re int y,re int v){
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[x]]) swap(x,y);
        change(1,st[top[x]],st[x],v);
        x=fa[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y);
    change(1,st[x],st[y],v);
}
int query(re int x,re int y){
    re int lastx=-1,lasty=-1,ans=0;
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]]) swap(x,y),swap(lastx,lasty);
        re tree k=query(1,st[top[x]],st[x]);
        ans+=(k.sum-(k.rcol==lastx));
        lastx=k.lcol;
        x=fa[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y),swap(lastx,lasty);
    re tree k=query(1,st[x],st[y]);
    ans+=k.sum-(k.lcol==lastx)-(k.rcol==lasty);
    return ans;
}
int main(){
    re int n,m;scanf("%d%d",&n,&m);
    for(re int i=1;i<=n;i++) scanf("%d",&a[i]);
    for(re int i=1;i<n;i++) {
        re int u=rd(),v=rd();
        add(u,v,0);
        add(v,u,0);
    }
    dep[1]=st[1]=pre[1]=st[0]=1;
    dfs(1,0);
    _dfs(1,1);
    build(1,1,n);
    while(m--){
        re char c=getchar();
        while(c!='Q'&&c!='C') c=getchar();
        if(c=='Q'){
            re int x,y;scanf("%d%d",&x,&y);
            // cout<<query(x,y)<<"\n";
            printf("%d\n",query(x,y));
        }
        else{
            re int x,y,v;
            scanf("%d%d%d",&x,&y,&v);
            change(x,y,v);
        }
    }
}