// luogu-judger-enable-o2

 //minamoto

 #include<bits/stdc++.h>

 #define N 300005

 using namespace std;

 template<class T>inline bool cmax(T&a,const T&b){return a<b?a=b,:;}

 inline int read(){

     #define num ch-'0'

     char ch;bool flag=;int res;

     while(!isdigit(ch=getchar()))

     (ch=='-')&&(flag=true);

     for(res=num;isdigit(ch=getchar());res=res*+num);

     (flag)&&(res=-res);

     #undef num

     return res;

 }

 int L[N<<],R[N<<],mx[N<<],sum[N<<];

 int sz[N],fa[N],son[N],dfn[N],rk[N],d[N],top[N],val[N],c[N];

 int ver[N<<],head[N],Next[N<<],yval[N],yc[N];

 int rt[N];

 int n,m,num,tot,cnt;

 inline void add(int u,int v){

     ver[++tot]=v,Next[tot]=head[u],head[u]=tot;

     ver[++tot]=u,Next[tot]=head[v],head[v]=tot;

 }

 void dfs1(int u){

     sz[u]=,d[u]=d[fa[u]]+;

     for(int i=head[u];i;i=Next[i]){

         if(ver[i]==fa[u]) continue;

         int v=ver[i];

         fa[v]=u;

         dfs1(v);

         sz[u]+=sz[v];

         if(!son[u]||sz[v]>sz[son[u]]) son[u]=v;

     }

 }

 void dfs2(int u){

     if(!top[u]) top[u]=u;

     dfn[u]=++num,rk[num]=u;

     if(!son[u]) return;

     top[son[u]]=top[u],dfs2(son[u]);

     for(int i=head[u];i;i=Next[i]){

         int v=ver[i];

         if(v!=fa[u]&&v!=son[u]) dfs2(v);

     }

 }

 void update(int p){

     mx[p]=max(mx[L[p]],mx[R[p]]);

     sum[p]=sum[L[p]]+sum[R[p]];

 }

 void modify(int &p,int l,int r,int k,int v){

     if(!p) p=++cnt;

     if(l>=r){

         mx[p]=sum[p]=v;return;

     }

     int mid=(l+r)>>;

     if(k<=mid) modify(L[p],l,mid,k,v);

     else modify(R[p],mid+,r,k,v);

     update(p);

     if(sum[p]==) p=;

 }

 int askmax(int p,int l,int r,int ql,int qr){

     if(!p) return -;

     if(ql<=l&&qr>=r) return mx[p];

     int mid=(l+r)>>,val=-;

     if(ql<=mid) cmax(val,askmax(L[p],l,mid,ql,qr));

     if(qr>mid) cmax(val,askmax(R[p],mid+,r,ql,qr));

     return val;

 }

 int asksum(int p,int l,int r,int ql,int qr){

     if(!p) return ;

     if(ql<=l&&qr>=r) return sum[p];

     int mid=(l+r)>>,val=;

     if(ql<=mid) val+=asksum(L[p],l,mid,ql,qr);

     if(qr>mid) val+=asksum(R[p],mid+,r,ql,qr);

     return val;

 }

 int path_max(int u,int v){

     int ans=-;

     int xz=yc[u];

     while(top[u]!=top[v]){

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

         cmax(ans,askmax(rt[xz],,num,dfn[top[u]],dfn[u]));

         u=fa[top[u]];

     }

     if(d[u]<d[v]) swap(u,v);

     cmax(ans,askmax(rt[xz],,num,dfn[v],dfn[u]));

     return ans;

 }

 int path_sum(int u,int v){

     int ans=;

     int xz=yc[u];

     while(top[u]!=top[v]){

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

         ans+=asksum(rt[xz],,num,dfn[top[u]],dfn[u]);

         u=fa[top[u]];

     }

     if(d[u]<d[v]) swap(u,v);

     ans+=asksum(rt[xz],,num,dfn[v],dfn[u]);

     return ans;

 }

 int main(){

     //freopen("testdata.in","r",stdin);

     int n,q;

     n=read(),q=read();

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

     yval[i]=read(),yc[i]=read();

     for(int i=;i<n;++i){

         int u=read(),v=read();

         add(u,v);

     }

     dfs1(),dfs2();

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

     modify(rt[yc[rk[i]]],,num,i,yval[rk[i]]);

     while(q--){

         char s[];int x,y;

         scanf("%s",s);

         x=read(),y=read();

         switch(s[]){

             case 'C':{

                 modify(rt[yc[x]],,num,dfn[x],);

                 yc[x]=y;

                 modify(rt[yc[x]],,num,dfn[x],yval[x]);

                 break;

             }

             case 'W':{

                 yval[x]=y;

                 modify(rt[yc[x]],,num,dfn[x],yval[x]);

                 break;

             }

             case 'S':{

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

                 break;

             }

             case 'M':{

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

                 break;

             }

         }

     }

     return ;

 }