#pragma GCC optimize("O3,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
const int N=2e5;
vector<vector<int>> g(N);
vector<int> tin(N), c(N), tout(N);
int leafs;
struct LCA {
int root, n, cnt;
vector<array<int, 21>> par;
vector<int> d;
LCA(int _n, int r){
n = _n;
par.resize(n);
d.assign(n, 0);
root = r; cnt = 0;
d[root] = -1;
dfs(root, root);
for (int i = 1; i < 21; i++){
for(int l = 0; l<n; l++){
par[l][i] = par[par[l][i-1]][i-1];
}
}
}
void dfs(int v, int p){
par[v][0] = p;
tin[v] = cnt++;
d[v] = d[p]+1;
for (auto i: g[v]){
if (i != p) dfs(i, v), c[v]+=c[i];
}
if(g[v].size()==1) c[v]++, leafs++;
tout[v] = cnt++;
}
bool ia(int u, int v){
return tin[u] <= tin[v] && tout[u] >= tout[v];
}
int operator()(int u, int v){
if(ia(u, v)) return u;
if(ia(v, u)) return v;
for(int i = 20; i>=0; i--){
if(!ia(par[u][i], v)) u=par[u][i];
}
return par[u][0];
}
int distance(int u, int v){
return d[u]+d[v]-2*d[(*this)(u, v)];
}
};
int32_t main(){
ios_base::sync_with_stdio(false); cin.tie(0);
int n, q; cin >> n >> q;
vector<array<int, 2>> count(n);
int root=0;
for(int i =0; i<n-1; i++){
int x, y; cin >> x >> y;
x--; y--;
g[x].push_back(y);
g[y].push_back(x);
if(g[x].size()>1) root = x;
if(g[y].size()>1) root = y;
}
LCA lca(n, root);
int ans = 0;
auto dfs2=[&](int v, int p, auto&& dfs2)->void{
//cout<<v+1<<" "<<c[v]<<"\n";
if(c[v] %2) count[v][1]++;
else count[v][0]++, ans++;
for(auto i: g[v]){
if(i!=p){
count[i][0]+=count[v][0];
count[i][1]+=count[v][1];
dfs2(i, v, dfs2);
}
}
};
dfs2(root, root, dfs2) ;
int tmpans = ans, tmpleafs=leafs;
while(q--){
int d; cin >> d;
vector<int> ar(d),a, up;
for(auto &i: ar) cin >> i, i--;
sort(ar.begin(), ar.end(), [&](int x, int y){
return tin[x] < tin[y];
});
int k=1;
for(int i=1; i<d; i++){
if(ar[i]==ar[i-1])k++;
else{
if(g[ar[i-1]].size()==1){
leafs+=k-1;
if(k%2==0) a.push_back(ar[i-1]);
k = 1;
}
else{
leafs+=k;
if(k%2==1) a.push_back(ar[i-1]);
k=1;
}
}
}
if(g[ar[d-1]].size()==1){
leafs+=k-1;
if(k%2==0) a.push_back(ar[d-1]);
}
else{
leafs+=k;
if(k%2==1) a.push_back(ar[d-1]);
}
up = a;
if(up.size()){
for(int i=0; i<a.size()-1; i++){
up.push_back(lca(a[i], a[i+1]));
}
sort(up.begin(), up.end(), [&](int x, int y){
return tin[x] < tin[y];
});
vector<int> upp;
for(int i=0; i<up.size(); i++){
if(i==0||up[i]!=up[i-1]) upp.push_back(up[i]);
}
up=upp;
upp.clear();
if(up.size()){
stack<int> st;
st.push(0);
vector<int> p(up.size()), v(up.size()), s(up.size());
vector<vector<int>> adj(up.size());
vector<int> aa(up.size());
sort(up.begin(), up.end(), [&](int x, int y){
return tin[x] < tin[y];
});
for(int i=1; i<up.size(); i++) {
while(st.size() && tout[up[st.top()]] < tin[up[i]]){
st.pop();
}
if(st.size())
adj[st.top()].push_back(i), aa[i]++, p[i]=st.top();
else p[i]=i;
st.push(i);
}
auto dfsa=[&](int ve, auto&&dfsa)->void{
for(auto i: adj[ve]){
dfsa(i, dfsa), v[ve]+=v[i];
}
};
int pos=0;
for(int l=0; l<a.size(); l++){
while(pos<up.size()&&up[pos]!=a[l]) pos++;
if(pos<up.size()&&up[pos]==a[l]) v[pos]++;
}
for(int i=0; i<up.size(); i++){
if(aa[i]==0) dfsa(i, dfsa);
}
for(int i=0; i<up.size(); i++){
if(p[i]==i){
auto x = count[up[i]];
if(v[i]%2){
ans-=x[0]; ans+=x[1];
}
}
else if(v[i]%2){
auto x=count[up[i]], y=count[up[p[i]]];
x[0]-=y[0];
x[1]-=y[1];
ans-=x[0]; ans+=x[1];
}
}
}
}
if((leafs%2)!=0) cout<<-1<<"\n";
else cout<<ans-1+d+n-1<<"\n";
ans=tmpans; leafs=tmpleafs;
}
}
