#include<iostream>
#include<cstdlib>
#include<cstdio>
#include<cstring>
#define MAXN 100005
using namespace std;
int n,q,w[MAXN],c[MAXN],head[MAXN],cnt=0;
int father[MAXN],top[MAXN],maxv[MAXN],siz[MAXN],deep[MAXN],pos[MAXN],sz=0;
int tot=0,rt[MAXN],ls[MAXN*100],rs[MAXN*100],maxn[MAXN*100],sum[MAXN*100];
int read()
{int x=0,f=1;char c=getchar();while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}return x*f;
}
struct Node1
{int next,to;
}Edges[MAXN*2];
void addedge(int u,int v)
{Edges[++cnt].next=head[u];head[u]=cnt;Edges[cnt].to=v;
}
void dfs1(int u)
{siz[u]=1;for(int i=head[u];~i;i=Edges[i].next){int v=Edges[i].to;if(v==father[u])continue;father[v]=u,deep[v]=deep[u]+1;dfs1(v);siz[u]+=siz[v];if(siz[v]>siz[maxv[u]])maxv[u]=v;}
}
void dfs2(int u,int t)
{top[u]=t;++sz,pos[u]=sz;if(maxv[u])dfs2(maxv[u],t);for(int i=head[u];~i;i=Edges[i].next){int v=Edges[i].to;if(v==maxv[u]||v==father[u])continue;dfs2(v,v);}
}
void update(int idx)
{sum[idx]=sum[ls[idx]]+sum[rs[idx]];maxn[idx]=max(maxn[ls[idx]],maxn[rs[idx]]);
}
void change(int &idx,int l,int r,int p,int w)
{if(!idx)++tot,idx=tot;if(l==r){maxn[idx]=sum[idx]=w;return;}int mid=(l+r)>>1;if(p<=mid)change(ls[idx],l,mid,p,w);else change(rs[idx],mid+1,r,p,w);update(idx);
}
int querysum(int idx,int l,int r,int L,int R)
{if(!idx)return 0;if(L==l&&R==r)return sum[idx];int mid=(l+r)>>1;if(R<=mid)return querysum(ls[idx],l,mid,L,R);else if(L>mid)return querysum(rs[idx],mid+1,r,L,R);else return querysum(ls[idx],l,mid,L,mid)+querysum(rs[idx],mid+1,r,mid+1,R);
}
int querymax(int idx,int l,int r,int L,int R)
{if(!idx)return 0;if(L==l&&R==r)return maxn[idx];int mid=(l+r)>>1;if(R<=mid)return querymax(ls[idx],l,mid,L,R);else if(L>mid)return querymax(rs[idx],mid+1,r,L,R);else return max(querymax(ls[idx],l,mid,L,mid),querymax(rs[idx],mid+1,r,mid+1,R));
}
int QS(int x,int y)
{int t=c[x],res=0;while(top[x]!=top[y]){if(deep[top[x]]<deep[top[y]])swap(x,y);res+=querysum(rt[t],1,sz,pos[top[x]],pos[x]);x=father[top[x]];}if(deep[x]<deep[y])swap(x,y);res+=querysum(rt[t],1,sz,pos[y],pos[x]);return res;
}int QM(int x,int y)
{int t=c[x],res=0;while(top[x]!=top[y]){if(deep[top[x]]<deep[top[y]])swap(x,y);res=max(res,querymax(rt[t],1,sz,pos[top[x]],pos[x]));x=father[top[x]];}if(deep[x]<deep[y])swap(x,y);res=max(res,querymax(rt[t],1,sz,pos[y],pos[x]));return res;
}
int main()
{memset(head,-1,sizeof(head));n=read(),q=read();for(int i=1;i<=n;i++)w[i]=read(),c[i]=read();for(int i=1;i<n;i++){int x=read(),y=read();addedge(x,y),addedge(y,x);}deep[1]=1;dfs1(1),dfs2(1,1);for(int i=1;i<=n;i++)change(rt[c[i]],1,sz,pos[i],w[i]);for(int i=1;i<=q;i++){char opt[5];scanf("%s",opt);int x=read(),y=read();if(opt[1]=='C'){change(rt[c[x]],1,sz,pos[x],0);change(rt[y],1,sz,pos[x],w[x]);c[x]=y;}else if(opt[1]=='W'){change(rt[c[x]],1,sz,pos[x],y);w[x]=y;}else if(opt[1]=='S')printf("%d\n",QS(x,y));else printf("%d\n",QM(x,y));}return 0;
}