#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
using namespace std;
#define N 500000
#define pos(i,a,b) for(int i=(a);i<=(b);i++)
int n,m;
int v[N];
struct haha
{
     int next,to;
}edge[N];
int head[N],cnt=1;
struct qian
{
  int left,right;
  int lcol,rcol,duan;
}tree[N];
int duan[N];
void add(int u,int v)
{
     edge[cnt].to=v;
     edge[cnt].next=head[u];
     head[u]=cnt++;
}
int rt[N];
int size[N],son[N],dep[N],fa[N];
void dfs1(int x)
{
    size[x]=1;son[x]=0;
    for(int i=head[x];i;i=edge[i].next)
    {
       int to=edge[i].to;
       if(to!=fa[x])
       {
          fa[to]=x;
          dep[to]=dep[x]+1;
          dfs1(to);
          size[x]+=size[to];
          if(size[to]>size[son[x]])
            son[x]=to;
       }
    }
}
int id[N],pos[N],top[N];
int ji;
void dfs2(int x,int tp)
{
     top[x]=tp;
     id[x]=++ji;
     pos[ji]=x;
     if(son[x])
       dfs2(son[x],tp);
     for(int i=head[x];i;i=edge[i].next)
     {
        int to=edge[i].to;
        if(to!=fa[x]&&to!=son[x])
          dfs2(to,to);
     }
}
void pushup(int root)
{
     tree[root].lcol=tree[root<<1].lcol;
     tree[root].rcol=tree[root<<1|1].rcol;
     if(tree[root<<1].rcol==tree[root<<1|1].lcol)
       tree[root].duan=tree[root<<1].duan+tree[root<<1|1].duan-1;
     else
       tree[root].duan=tree[root<<1].duan+tree[root<<1|1].duan;
}
void build(int left,int right,int root)
{
     rt[root]=-1;
     tree[root].left=left;
     tree[root].right=right;
     if(left==right)
     {
        tree[root].lcol=tree[root].rcol=v[pos[left]];
        tree[root].duan=1;
        return;
     }
     int mid=(left+right)>>1;
     build(left,mid,root<<1);
     build(mid+1,right,root<<1|1);
     pushup(root);
}
void pushdown(int root)
{
     if(rt[root]>=0)
     {
        rt[root<<1]=rt[root];
        rt[root<<1|1]=rt[root];
        tree[root<<1].lcol=tree[root<<1].rcol=rt[root];
        tree[root<<1|1].lcol=tree[root<<1|1].rcol=rt[root];
        tree[root<<1].duan=tree[root<<1|1].duan=1;
        rt[root]=-1;
     }
}
void change(int left,int right,int num,int root)
{
     if(left<=tree[root].left&&right>=tree[root].right)
     {
        rt[root]=num;
        tree[root].lcol=tree[root].rcol=num;
        tree[root].duan=1;
        return;
     }
     pushdown(root);
     int mid=(tree[root].right+tree[root].left)>>1;
     if(left<=mid)
       change(left,right,num,root<<1);
     if(right>mid)
       change(left,right,num,root<<1|1);
     pushup(root);
}
int query(int left,int right,int root)
{
    if(left<=tree[root].left&&right>=tree[root].right)
      return tree[root].duan;
    pushdown(root);
    int mid=(tree[root].left+tree[root].right)>>1;
    if(right<=mid)
       return query(left,right,root<<1);
    else
      if(left>mid)
         return query(left,right,root<<1|1);
      else
      {
          int tmp=1;
          if(tree[root<<1].rcol!=tree[root<<1|1].lcol)
            tmp=0;
          return query(left,mid,root<<1)+query(mid+1,right,root<<1|1)-tmp;
      }
}

int temp1,temp2;
void check(int po,int root)
{
    pushdown(root);
    if(tree[root].left==tree[root].right)
    {
       temp1=tree[root].lcol;
       return;
    }
    int mid=(tree[root].right+tree[root].left)>>1;
    if(po<=mid)
       check(po,root<<1);
    else
       check(po,root<<1|1);
}
void check2(int po,int root)
{
    pushdown(root);
    if(tree[root].left==tree[root].right)
    {
       temp2=tree[root].lcol;
       return;
    }
    int mid=(tree[root].right+tree[root].left)>>1;
    if(po<=mid)
       check2(po,root<<1);
    else
       check2(po,root<<1|1);
}

int erx,fux,ery,fuy;
int Query(int x,int y)
{
    int fx=top[x],fy=top[y];
    int ans=0;
    while(fx!=fy)
    {
       if(dep[fx]>dep[fy])
       {
           check(id[fa[fx]],1);
           check2(id[fx],1);
           ans+=query(id[fx],id[x],1);
           if(temp1==temp2)
             ans--;

           x=fa[fx];
           fux=x;
           erx=fx;
           fx=top[x];
       }
       else
       {
           check(id[fa[fy]],1);
           check2(id[fy],1);
           ans+=query(id[fy],id[y],1);
           if(temp1==temp2)
             ans--;

           y=fa[fy];
           fuy=y;
           ery=fy;
           fy=top[y];

       }

    }
    if(dep[x]>dep[y])
    {
      //check(id[erx],1);
      //check(id[fux],1);
      ans+=query(id[y],id[x],1);
      //if(temp1==temp2)
       //ans--;
    }
    else
    {
      //check(id[ery],1);
      //check(id[fuy],1);
      ans+=query(id[x],id[y],1);
      //if(temp1==temp2)
       //ans--;
    }
    return ans;
}
void Change(int x,int y,int z)
{
     int fx=top[x],fy=top[y];
     while(fx!=fy)
     {
        if(dep[fx]<dep[fy])
        {
          swap(fx,fy);
          swap(x,y);
        }
        change(id[fx],id[x],z,1);
        x=fa[fx];fx=top[x];
     }
     if(dep[x]>dep[y])
      swap(x,y);
     change(id[x],id[y],z,1);
}
int read()
{
    int su=0;
    char ch=getchar();
    while(ch<'0'||ch>'9')
       ch=getchar();
    while(ch<='9'&&ch>='0')
    {
                           su=su*10+ch-'0';
                           ch=getchar();
    }

    return su;
}
int main()
{
    //freopen("paint6.in","r",stdin);
    //freopen("paint66.out","w",stdout);
    scanf("%d%d",&n,&m);
    pos(i,1,n)
      v[i]=read();
    pos(i,1,n-1)
    {
       int x,y;
       x=read();y=read();
       add(x,y);
       add(y,x);
    }
    dfs1(1);
    dfs2(1,1);
    build(1,n,1);
    pos(i,1,m)
    {
       char p;
       int x,y,z;
       scanf("%s",&p);
       if(p=='C')
       {
          x=read();y=read();z=read();
          Change(x,y,z);
       }
       if(p=='Q')
       {
          x=read();y=read();
          printf("%d\n",Query(x,y));
       }
    }
    //while(1);
    return 0;
}