// #pragma GCC optimize("O3,Ofast,unroll-loops")
// #pragma GCC target("avx2,bmi,popcnt")
#include <bits/stdc++.h>
#define lli long long int
#define ld long double
#define REP(i, n) for(int i = 0; (i) < (n); (i)++)
#define all(x) x.begin(), x.end();
#define rall(x) x.rbegin(), x.rend()
#define pb push_back
#define MP make_pair
using namespace std;
void fastio() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
}
const int N = 2e5 + 5;
const int INF = 1e9 + 500;
const int MOD = 1e9 + 7;
int n, q;
vector<vector<int> > adj(N, vector<int>());
int ans = 0;
int dfs(int node, int par) {
if(adj[node].size() == 1 && par) {
ans++;
// cout << "node: " << node << " 1" << "\n";
return 1;
}
int ret = 0;
if(par == 0 && adj[node].size() == 1) ret++;
for(auto c : adj[node]) {
if(c == par) continue;
ret += dfs(c, node);
}
// cout << "node: " << node << " ret:" << ret << "\n";
if(par == 0) {
if(ret & 1) return -1;
return ans;
}
if(ret & 1) {
ans++;
return 1;
}
else {
ans += 2;
return 2;
}
}
void solve() {
cin >> n >> q;
REP(i, n - 1) {
int u, v;
cin >> u >> v;
adj[u].pb(v);
adj[v].pb(u);
}
REP(z, q) {
int d;
cin >> d;
ans = 0;
// fill(dp.begin(), dp.begin() + n + d + 3, 0);
for(int i = n + 1; i <= n + d; i++) {
int x;
cin >> x;
adj[i].pb(x);
adj[x].pb(i);
}
int res = dfs(1, 0);
cout << res << "\n";
for(int i = n + 1; i <= n + d; i++) {
for(auto j : adj[i]) {
adj[j].pop_back();
}
adj[i].clear();
}
}
}
signed main() {
fastio();
solve();
}
