#include <bits/stdc++.h>
#define ios ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0)
#define file(s) if (fopen(s".in", "r")) freopen(s".in", "r", stdin), freopen(s".out", "w", stdout)
#define all(a) a.begin() , a.end()
#define F first
#define S second
using namespace std;
using ll = long long;
const ll N = 2e5+5 , inf = 2e9 + 7;
const ll INF = 1e18 , mod = 1e9+7;
ll a[N] , b[N] , mx , mx2 , par[N] , was[N] , dp[N];
vector<int> g[N] , vec;
map<pair<int,int> ,int> mp;
void dfs(int v, int p){
par[v] = p;
// cout << v <<" " << dp[v] << "\n";
if(mx != v && dp[v] > dp[mx2] && was[v] == 0 && g[v].size() == 1) mx2 = v;
for(int to : g[v]){
if(to != p){
if(mp[{v,to}] == 1){
dp[to] = dp[v]-1;
} else {
dp[to] = dp[v]+1;
}
dfs(to,v);
}
}
}
void solve(){
int n , q;
cin >> n >> q;
for(int i = 1; i < n; i++){
cin >> a[i] >> b[i];
}
while(q--){
int k;
cin >> k;
for(int i = 1; i <= n+k; i++) g[i].clear() , was[i] = par[i] = 0;
for(int i = 1; i < n; i++){
g[a[i]].push_back(b[i]);
g[b[i]].push_back(a[i]);
}
for(int i = 1; i <= k; i++){
int a;
cin >> a;
g[a].push_back(i+n);
g[i+n].push_back(a);
}
int res = 0;
for(int i = 1; i <= n+k; i++){
if(g[i].size() == 1) res++;
}
// cout << res << "\n";
// return;
if(res % 2){
cout << "-1\n";
continue;;
}
// return;
int ans = 0 , cnt = 0;
mp.clear();
// int k1 = 4;
dp[n+k+1] = -inf;
while(1){
for(int i = 1; i <= n+k; i++) dp[i] = 0;
for(int i = 1; i <= n+k; i++){
if(g[i].size() == 1 && was[i] == 0){
mx = i;
break;
}
}
mx2 = n+k+1;
dp[mx] = 0;
dfs(mx,0);
mx = mx2;
mx2 = n+k+1;
dp[mx] = 0;
dfs(mx,0);
// cout << mx <<" " << mx2 <<"\n";
mx = mx2;
vector<int> path;
while(mx > 0){
path.push_back(mx);
mx = par[mx];
}
// cout << path[0] <<" " << path.back() <<"\n";
for(int i = 0; i + 1 < path.size(); i++){
if(mp[{path[i] , path[i+1]}] == 0){
cnt++;
}
mp[{path[i],path[i+1]}] = 1;
mp[{path[i+1],path[i]}] = 1;
}
was[path.back()] = was[path[0]] = 1;
ans += path.size()-1;
if(cnt == n+k-1) break;
}
cout << ans << "\n";
}
}
/*
*/
signed main(){
ios;
solve();
}
