#include<bits/stdc++.h>
using namespace std;
int inf=1e9+5;
int kaf=(1<<18);
struct segment{
pair<int,int>seg[(1<<19)];
vector<int>unnow;
segment(){
for(int i=0;i<(1<<19);i++){
seg[i]=make_pair(inf,inf);
}
}
void clear(){
for(auto x:unnow){
seg[x]=make_pair(inf,inf);
}
unnow.clear();
}
void upd(int i,int l,int r,int tl,int tr,pair<int,int>w){
if(l>r||l>tr||r<tl){
return ;
}
if(l>=tl&&r<=tr){
unnow.push_back(i);
seg[i]=min(seg[i],w);
return ;
}
int m=(l+r)>>1;
upd((i<<1),l,m,tl,tr,w);
upd((i<<1)^1,m+1,r,tl,tr,w);
}
pair<int,int>pors(int i){
if(i==0){
return seg[i];
}
pair<int,int>ret=min(seg[i],pors(i>>1));
return ret;
}
};
segment seg;
int n,m,rishe;
const int maxn=100000+5;
vector<int>bache[maxn],adj[maxn],fakeadj[maxn];
int timea=0,sz[maxn],fakesz[maxn],mainres=0,cnt=0,fakeres,fakecnt;
pair<int,int>stf[maxn],flca[20][maxn];
int lca[20][maxn],vis[maxn],high[maxn];
void dfs(int u,int par){
high[u]=high[par]+1;
timea++;
lca[0][u]=par;
stf[u].first=timea;
for(auto x:adj[u]){
if(x!=par){
dfs(x,u);
sz[u]+=sz[x];
bache[u].push_back(x);
}
}
if(adj[u].size()==1)
{
cnt++;
sz[u]=1;
}
stf[u].second=timea;
if((sz[u]&1)==0&&u!=rishe){
mainres++;
}
}
void callca(){
for(int i=0;i<20;i++){
for(int j=1;j<=n;j++){
if(i==0){
if(sz[j]&1){
flca[i][j]=make_pair(1,0);
}
else{
flca[i][j]=make_pair(0,1);
}
continue;
}
flca[i][j].first=flca[i-1][j].first+flca[i-1][lca[i-1][j]].first;
flca[i][j].second=flca[i-1][j].second+flca[i-1][lca[i-1][j]].second;
lca[i][j]=lca[i-1][lca[i-1][j]];
}
}
}
bool cmp(int a,int b){
return stf[a].first<stf[b].first;
}
bool zird(int u,int v){
if(stf[u].first<=stf[v].first&&stf[u].second>=stf[v].second){
return 1;
}
return 0;
}
int justlca(int u,int v){
if(u==v){
return u;
}
if(zird(u,v)){
return v;
}
if(zird(v,u)){
return u;
}
for(int i=19;i>=0;i--){
if(lca[i][u]==0){
continue;
}
if(!zird(lca[i][u],v)){
u=lca[i][u];
}
}
u=lca[0][u];
return u;
}
pair<int,int>getlca(int u,int v){
if(u==v){
return make_pair(0,0);
}
pair<int,int>ret={0,0};
for(int i=19;i>=0;i--){
if(lca[i][u]==0){
continue;
}
if(!zird(lca[i][u],v)){
ret.first+=flca[i][u].first;
ret.second+=flca[i][u].second;
// cout<<i<<" "<<u<<" "<<v<<" "<<flca[i][u].first<<" "<<flca[i][u].second<<"\n";
u=lca[i][u];
}
}
// cout<<"paru "<<u<<" "<<v<<" "<<flca[0][u].first<<" "<<flca[0][u].second<<"\n";
ret.first+=flca[0][u].first;
ret.second+=flca[0][u].second;
u=lca[0][u];
return ret;
}
void solve(int u,int par=0){
for(auto x:fakeadj[u]){
// cout<<"par:bach "<<u<<" "<<x<<"\n";
solve(x,u);
fakesz[u]+=fakesz[x];
}
//cout<<u<<" "<<fakesz[u]<<"\n";
if(fakesz[u]&1){
if(par!=0){
pair<int,int>chen=getlca(u,par);
fakeres-=chen.second;
fakeres+=chen.first;
}
}
}
int main(){
// freopen("input1.txt","r",stdin);
// freopen("outy.txt","w",stdout);
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin>>n>>m;
for(int i=0;i<n-1;i++){
int u,v;
cin>>u>>v;
adj[u].push_back(v);
adj[v].push_back(u);
}
for(int i=1;i<=n;i++){
if((int)adj[i].size()>1){
rishe=i;
break;
}
}
dfs(rishe,0);
callca();
//cout<<mainres<<"\n";
for(int asd=0;asd<m;asd++){
//seg.clear();
int di;
cin>>di;
vector<int>alld;
vector<int>remove;
fakeres=mainres,fakecnt=cnt;
for(int i=0;i<di;i++){
seg.clear();
int dd;
cin>>dd;
remove.push_back(dd);
alld.push_back(dd);
if((int)adj[dd].size()==1&&vis[dd]==0){
vis[dd]=1;
continue;
}
fakecnt++;
fakesz[dd]++;
}
if((int)alld.size()==0){
//cout<<"salam\n";
if(fakecnt&1){
cout<<-1<<"\n";
}
else{
fakeres+=n-1;
fakeres+=di;
cout<<fakeres<<"\n";
}
for(auto x:remove){
fakeadj[x].clear();
fakesz[x]=0;
sz[x]=0;
vis[x]=0;
}
continue;
}
//alld.push_back(rishe);
sort(alld.begin(),alld.end(),cmp);
vector<int>fake=alld;
for(int i=1;i<(int)alld.size();i++){
fake.push_back(justlca(alld[i],alld[i-1]));
}
fake.push_back(rishe);
sort(fake.begin(),fake.end());
vector<int>alln;
alln.push_back(fake[0]);
for(int i=1;i<(int)fake.size();i++){
if(fake[i]!=fake[i-1]){
alln.push_back(fake[i]);
}
}
sort(alln.begin(),alln.end(),cmp);
for(int i=0;i<(int)alln.size();i++){
pair<int,int>wp=seg.pors(kaf+stf[alln[i]].first);
// cout<<alln[i]<<" asd "<<wp.first<<" "<<wp.second<<"\n";
if(wp.first!=inf){
fakeadj[wp.second].push_back(alln[i]);
}
seg.upd(1,0,kaf-1,stf[alln[i]].first,stf[alln[i]].second,make_pair(-high[alln[i]],alln[i]));
}
solve(alln[0]);
if(fakecnt&1){
cout<<-1<<"\n";
}
else{
fakeres+=n-1;
fakeres+=di;
cout<<fakeres<<"\n";
}
for(auto x:remove){
fakeadj[x].clear();
fakesz[x]=0;
sz[x]=0;
vis[x]=0;
}
for(auto x:alln){
fakeadj[x].clear();
fakesz[x]=0;
sz[x]=0;
vis[x]=0;
}
}
}
