#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;
int a[N] , b[N] , sz[N];
vector<int> g[N];
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();
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++) res += (g[i].size() == 1);
if(res % 2){
cout << "-1\n";
continue;
}
int cnt = 0;
for(int i = 2; i <= n; i++){
sz[i] = g[i].size()-1;
if(sz[i] >= 3) sz[i] %= 2;
if(sz[i] == 2) cnt++;
}
cout << n+k-1+cnt << "\n";
}
}
/*
*/
signed main(){
ios;
solve();
}
