#include <bits/stdc++.h>
#define ll long long
#define dbg(x) cerr << #x << ' ' << x << endl;
#define inf 1e18
using namespace std;
void printvec(vector<ll>& vec)
{
for (auto &&e : vec)
{
cout << e << ' ';
}
cout << endl;
}
vector<pair<ll,ll>> parr;
ll solve(vector<vector<ll>>& adj, ll node, ll par, ll& ans)
{
if(node!=par && adj[node].size()==1)
{
parr[node]={par,1};
ans++;
return 1;
}
ll sm=0;
for (auto &&e : adj[node])
{
if(e==par)continue;
ll val=solve(adj,e,node,ans);
sm+=val;
if(val%2)ans++;
else ans+=2;
}
if(adj[node].size()==1 && node==0) sm++;
parr[node]={par,sm%2};
if(parr[node].second==0)ans+=2;
if(node==0 && sm%2)ans=-1;
return sm;
}
void climb(ll node, ll& ans)
{
while(node!=0)
{
if(parr[node].second==0)
{
ans--;
}
else ans++;
parr[node].second^=1;
node=parr[node].first;
}
}
int main()
{
cin.tie(0);
ios_base::sync_with_stdio(false);
ll n, q;
cin>>n>>q;
parr.resize(n);
vector<vector<ll>> adj(n);
for (int i=0;i<n-1;i++)
{
ll u, v;
cin>>u>>v;
u--;v--;
adj[u].push_back(v);
adj[v].push_back(u);
}
while(q--)
{
ll cur=n;
ll d;
cin>>d;
vector<vector<ll>> newadj=adj;
for (int i=0;i<d;i++)
{
ll nd;
cin>>nd;
nd--;
newadj[nd].push_back(cur++);
newadj.push_back({nd});
}
ll ans=0;
solve(newadj,0,0,ans);
cout << ans << endl;
}
}
