2325

#include<cstdio>
#include<iostream>
#define LL long long
#define inf 0x7ffffff
#define pa pair<int,int>
#define pi 3.1415926535897932384626433832795028841971
using namespace std;
inline LL read()
{
    LL x=0,f=1;char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
    return x*f;
}
int n,m,cnt,tt,x0,y0,x1,y1;
struct segtree{
    int l,r;
    int a_to_a,a_to_b,b_to_a,b_to_b;
}tree[1000010];
struct edge{
    int to,next;
}e[200010];
int head[100010];
segtree query;
bool mrk[100010],mrkl[100010],mrkr[100010];
int fa[100010][20],depth[100010],son[100010];
int chain[100010],belong[100010],place[100010],pplace[100010];
inline int max(int a,int b,int c,int d)
{
	if (b>a)a=b;
	if (c>a)a=c;
	if (d>a)a=d;
	return a;
}
inline void ins(int u,int v)
{
    e[++cnt].to=v;
    e[cnt].next=head[u];
    head[u]=cnt;
}
inline void insert(int u,int v)
{
    ins(u,v);
    ins(v,u);
}
inline void dfs1(int x,int dep)
{
    if (mrk[x])return;mrk[x]=1;
    son[x]=1;depth[x]=dep;
    for (int i=1;i<20;i++)
      fa[x][i]=fa[fa[x][i-1]][i-1];
    for (int i=head[x];i;i=e[i].next)
      if (!mrk[e[i].to])
      {
        fa[e[i].to][0]=x;
        dfs1(e[i].to,dep+1);
        son[x]+=son[e[i].to];
      }
}
inline void dfs2(int x,int chain)
{
    place[x]=++tt;pplace[tt]=x;
    belong[x]=chain;
    int mx=-1,res=-1;
    for (int i=head[x];i;i=e[i].next)
      if (e[i].to!=fa[x][0])
        {
            if (son[e[i].to]>mx)
            {
                mx=son[e[i].to];
                res=e[i].to;
            }
        }
    if (res==-1)return;
    dfs2(res,chain);
    for (int i=head[x];i;i=e[i].next)
      if (res!=e[i].to&&fa[x][0]!=e[i].to)
      dfs2(e[i].to,e[i].to);
}
inline int LCA(int x,int y)
{
    if (depth[x]<depth[y])swap(x,y);
    int res=depth[x]-depth[y];
    for (int i=0;i<20;i++)
      if (res & (1<<i))x=fa[x][i];
    for (int i=19;i>=0;i--)
      if (fa[x][i]!=fa[y][i])
        {
            x=fa[x][i];
            y=fa[y][i];
        }
    if (x==y)return x;
    return fa[x][0];
}
segtree merge(segtree a,segtree b)
{
    segtree k;
    k.a_to_a=k.a_to_b=k.b_to_a=k.b_to_b=-1;
    k.l=min(a.l,b.l); k.r=max(a.r,b.r);
     
    if (a.a_to_a!=-1&&b.a_to_a!=-1)k.a_to_a=a.a_to_a+b.a_to_a+1;
    if (a.a_to_b!=-1&&b.b_to_a!=-1)
    {
        if (k.a_to_a==-1)k.a_to_a=a.a_to_b+b.b_to_a+1;
        else k.a_to_a=min(k.a_to_a,a.a_to_b+b.b_to_a+1);
    }
     
    if (a.a_to_a!=-1&&b.a_to_b!=-1)k.a_to_b=a.a_to_a+b.a_to_b+1;
    if (a.a_to_b!=-1&&b.b_to_b!=-1)
    {
        if (k.a_to_b==-1)k.a_to_b=a.a_to_b+b.b_to_b+1;
        else k.a_to_b=min(k.a_to_b,a.a_to_b+b.b_to_b+1);
    }
     
    if (a.b_to_a!=-1&&b.a_to_a!=-1)k.b_to_a=a.b_to_a+b.a_to_a+1;
    if (a.b_to_b!=-1&&b.b_to_a!=-1)
    {
        if (k.b_to_a==-1)k.b_to_a=a.b_to_b+b.b_to_a+1;
        else k.b_to_a=min(k.b_to_a,a.b_to_b+b.b_to_a+1);
    }
     
    if (a.b_to_a!=-1&&b.a_to_b!=-1)k.b_to_b=a.b_to_a+b.a_to_b+1;
    if (a.b_to_b!=-1&&b.b_to_b!=-1)
    {
        if (k.b_to_b==-1)k.b_to_b=a.b_to_b+b.b_to_b+1;
        else k.b_to_b=min(k.b_to_b,a.b_to_b+b.b_to_b+1);
    }
    return k;
}
inline void buildtree(int now,int l,int r)
{
    tree[now].l=l;tree[now].r=r;
    if (l==r)
    {
        tree[now].a_to_a=tree[now].a_to_b=tree[now].b_to_a=tree[now].b_to_b=-1;
        if (mrkl[pplace[l]])tree[now].a_to_a=0;
        if (mrkr[pplace[l]])tree[now].b_to_b=0;
        if (mrkl[pplace[l]]&&mrkr[pplace[r]])
        {
            tree[now].a_to_b=1;
            tree[now].b_to_a=1;
        }
        return;
    }
    int mid=(l+r)>>1;
    buildtree(now<<1,l,mid);
    buildtree(now<<1|1,mid+1,r);
    tree[now]=merge(tree[now<<1],tree[now<<1|1]);
}
inline segtree ask_in_tree(int now,int x,int y)
{
    int l=tree[now].l,r=tree[now].r;
    if (l==x&&r==y)return tree[now];
    int mid=(l+r)>>1;
    if (y<=mid)return ask_in_tree(now<<1,x,y);
    else if (x>mid)return ask_in_tree(now<<1|1,x,y);
    else return merge(ask_in_tree(now<<1,x,mid),ask_in_tree(now<<1|1,mid+1,y));
}
inline segtree ask(int from,int to)
{
    int l,r;
    segtree s;s.l=s.r=0;
    while (belong[from]!=belong[to])
    {
        l=place[belong[from]];
        r=place[from];
        if (!s.l)s=ask_in_tree(1,l,r);
            else s=merge(s,ask_in_tree(1,l,r));
        from=fa[belong[from]][0];
    }
    l=place[to];
    r=place[from];
    if (!s.l)s=ask_in_tree(1,l,r);
        else s=merge(s,ask_in_tree(1,l,r));
    return s;
}
inline void cal()
{
    int a=read(),b=read(),lca=LCA(a,b);
    segtree q1=ask(a,lca);
    segtree q2=ask(b,lca);
    swap(q2.a_to_b,q2.b_to_a);
    q1=merge(q1,q2);
    int ans=max(q1.a_to_a,q1.a_to_b,q1.b_to_a,q1.b_to_b);
    printf("%d\n",ans);
}
inline void change_in_tree(int now,int x,bool m1,bool m2)
{
    int l=tree[now].l,r=tree[now].r;
    if (l==r)
    {
        tree[now].a_to_a=tree[now].a_to_b=tree[now].b_to_a=tree[now].b_to_b=-1;
        if (m1)tree[now].a_to_a=0;
        if (m2)tree[now].b_to_b=0;
        if (m1&&m2)tree[now].a_to_b=tree[now].b_to_a=1;
        return;
    }
    int mid=(l+r)>>1;
    if (x<=mid)change_in_tree(now<<1,x,m1,m2);
    else change_in_tree(now<<1|1,x,m1,m2);
    tree[now]=merge(tree[now<<1],tree[now<<1|1]);
}
inline void wrk()
{
    int a=read();
    bool m1=0,m2=0;
    char ch=getchar();while (ch!=‘.‘&&ch!=‘#‘)ch=getchar();
    if (ch==‘.‘)m1=1;
    ch=getchar();while (ch!=‘.‘&&ch!=‘#‘)ch=getchar();
    if (ch==‘.‘)m2=1;
    change_in_tree(1,belong[a],m1,m2);
}
int main()
{
    n=read();m=read();
    for (int i=1;i<n;i++)
    {
        int x=read(),y=read();
        insert(x,y);
    }
    for(int i=1;i<=n;i++)
    {
    	char ch=getchar();while (ch!=‘#‘&&ch!=‘.‘)ch=getchar();
        if (ch==‘.‘)mrkl[i]=1;
        ch=getchar();while (ch!=‘#‘&&ch!=‘.‘)ch=getchar();
        if (ch==‘.‘)mrkr[i]=1;
    }
    dfs1(1,0);
    dfs2(1,1);
    buildtree(1,1,n);
    for(int i=1;i<=m;i++)
    {
        char opr=getchar();
        while (opr!=‘Q‘&&opr!=‘C‘)opr=getchar();
        if (opr==‘Q‘)cal();
        if (opr==‘C‘)wrk();
    }
    return 0;
}