#include<cstdio>

 #include<algorithm>

 #define lc ch[x][0]

 #define rc ch[x][1]

 #define ls (x<<1)

 #define rs (ls|1)

 #define lson ls,L,mid

 #define rson rs,mid+1,R

 #define rep(i,l,r) for (int i=(l); i<=(r); i++)

 #define For(i,x) for (int i=h[x],k; i; i=nxt[i])

 typedef long long ll;

 using namespace std;

 const int N=;

 char op[];

 ll tag[N<<],sm[N<<];

 int n,m,u,v,x,rt,cnt,tim,rev[N],h[N],nxt[N<<],to[N<<];

 int L[N],R[N],dep[N],fa[N][],ch[N][],sz[N],f[N];

 void add(int u,int v){ to[++cnt]=v; nxt[cnt]=h[u]; h[u]=cnt; }

 inline int rd(){

     int x=; char ch=getchar(); bool f=;

     while (ch<'' || ch>'') f|=ch=='-',ch=getchar();

     while (ch>='' && ch<='') x=(x<<)+(x<<)+(ch^),ch=getchar();

     return f ? -x : x;

 }

 int jump(int x,int k){

     for (int i=; ~i; i--) if (k&(<<i)) x=fa[x][i]; return x;

 }

 void push(int x,int L,int R){

     if (!tag[x]) return;

     int mid=(L+R)>>;

     sm[ls]+=tag[x]*(mid-L+); tag[ls]+=tag[x];

     sm[rs]+=tag[x]*(R-mid); tag[rs]+=tag[x];

     tag[x]=;

 }

 void mdf(int x,int L,int R,int l,int r,int k){

     if (L==l && r==R){ sm[x]+=1ll*k*(R-L+); tag[x]+=k; return; }

     int mid=(L+R)>>; push(x,L,R);

     if (r<=mid) mdf(lson,l,r,k);

     else if (l>mid) mdf(rson,l,r,k);

         else mdf(lson,l,mid,k),mdf(rson,mid+,r,k);

     sm[x]=sm[ls]+sm[rs];

 }

 ll que(int x,int L,int R,int l,int r){

     if (L==l && r==R) return sm[x];

     int mid=(L+R)>>; push(x,L,R);

     if (r<=mid) return que(lson,l,r);

     else if (l>mid) return que(rson,l,r);

         else return que(lson,l,mid)+que(rson,mid+,r);

 }

 void dfs(int x){

     L[x]=++tim; dep[x]=dep[fa[x][]]+; sz[x]=;

     rep(i,,) fa[x][i]=fa[fa[x][i-]][i-];

     mdf(,,n,L[x],L[x],dep[x]);

     For(i,x) if ((k=to[i])!=fa[x][]) fa[k][]=x,f[k]=x,dfs(k),sz[x]+=sz[k];

     R[x]=tim;

 }

 bool isrt(int x){ return (!f[x]) || (ch[f[x]][]!=x && ch[f[x]][]!=x); }

 void put(int x){ swap(lc,rc); rev[x]^=; }

 void push(int x){ if (rev[x]) put(lc),put(rc),rev[x]=; }

 void pd(int x){ if (!isrt(x)) pd(f[x]); push(x); }

 void rot(int x){

     int y=f[x],z=f[y],w=ch[y][]==x;

     if (!isrt(y)) ch[z][ch[z][]==y]=x;

     f[x]=z; f[y]=x; f[ch[x][w^]]=y;

     ch[y][w]=ch[x][w^]; ch[x][w^]=y;

 }

 void splay(int x){

     pd(x);

     while (!isrt(x)){

         int y=f[x],z=f[y];

         if (!isrt(y)) (ch[z][]==y)^(ch[y][]==x) ? rot(x) : rot(y);

         rot(x);

     }

 }

 void work(int x,int k){

     if (rt==x) mdf(,,n,,n,k);

     else if (L[rt]>=L[x] && L[rt]<=R[x]){

         int t=jump(rt,dep[rt]-dep[x]-);

         if (L[t]>) mdf(,,n,,L[t]-,k);

         if (R[t]<n) mdf(,,n,R[t]+,n,k);

     }else mdf(,,n,L[x],R[x],k);

 }

 int find(int x){

     push(x);

     while (lc) x=lc,push(x);

     return x;

 }

 void access(int x){

     for (int y=; x; y=x,x=f[x]){

         splay(x);

         if (rc) work(find(rc),);

         if (y) work(find(y),-);

         rc=y;

     }

 }

 void mkrt(int x){ access(x); splay(x); put(x); }

 int main(){

     freopen("bzoj3779.in","r",stdin);

     freopen("bzoj3779.out","w",stdout);

     n=rd(); m=rd();

     rep(i,,n) u=rd(),v=rd(),add(u,v),add(v,u);

     dfs(); rt=;

     while (m--){

         scanf("%s",op); x=rd();

         if (op[]=='L') access(x);

         if (op[]=='C') mkrt(x),rt=x;

         if (op[]=='Q'){

             if (rt==x) printf("%.10lf\n",.*que(,,n,,n)/n);

             else if (L[rt]>=L[x] && L[rt]<=R[x]){

                 int t=jump(rt,dep[rt]-dep[x]-);

                 ll res1=L[t]> ? que(,,n,,L[t]-) : ;

                 ll res2=R[t]<n ? que(,,n,R[t]+,n) : ;

                 printf("%.10lf\n",.*(res1+res2)/(n-sz[t]));

             }else printf("%.10lf\n",.*que(,,n,L[x],R[x])/sz[x]);

         }

     }

     return ;

 }