#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
#define int ll
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 , par[N] , was[N] , dp[N];
vector<int> g[N] , vec;
void dfs(int v, int p){
dp[v] = dp[p]+1;
par[v] = p;
if(dp[v] > dp[mx]) mx = v;
for(int to : g[v]){
if(to != p){
dfs(to,v);
}
}
}
void go(int v , int p){
dp[v] = dp[p]+1;
for(int to : g[v]){
if(to != p && was[to] == 0){
go(to,v);
}
}
if(g[v].size() == 1){
vec.push_back(dp[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);
}
ll cur = 0 , res = 0;
was[1] = 1;
for(int to : g[1]){
vec.clear();
dp[1] = 0;
go(to,1);
sort(all(vec));
ll ans = 0;
if(vec.size() == 1){
ans = 0;
} else if(vec.size() % 2){
ans = vec[0];
} else {
ans = vec[0]+vec[1];
}
// cout << to <<" " << ans << "\n";
res += vec.size();
cur += ans;
}
if(res % 2) cout << "-1\n";
else cout << cur+n+k-1 << "\n";
}
}
/*
*/
signed main(){
ios;
solve();
}
