#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tt;
#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())
pii refineTree (vector<vector<pii>> &graph, vector<int> &weight, vector<int> &node, int n, int root) {
vector<int> vis(n + 1), deg(n + 1);
queue<int> q;
for (int i = 1; i <= n; i++)
if (graph[i].size() == 1 && i != root) q.push(i);
for (int u : node) deg[u] = 1;
int ans = 0;
while (q.size()) {
int a = q.front(); q.pop();
if (vis[a] == graph[a].size()) continue;
vis[a]++;
for (auto [b, id] : graph[a]) {
if (vis[b] == graph[b].size()) continue;
if (deg[a]) deg[b] ^= 1, ans += weight[id];
else weight[id] = 0;
if (++vis[b] + 1 == graph[b].size()) q.push(b);
}
}
return {ans, (deg[root] == 0)};
}
const int mn = 1e5 + 5;
int up[mn][17], num[mn], sz[mn], dist[mn], depth[mn], timeDfs;
vector<vector<pii>> adj;
vector<int> weight;
void dfs (int u, int p, int d, int fromP) {
dist[u] = dist[p] + fromP, num[u] = ++timeDfs, sz[u] = 1;
up[u][0] = p, depth[u] = d;
for (int i = 1; i < 17; i++)
up[u][i] = up[up[u][i - 1]][i - 1];
for (auto [v, id] : adj[u]) {
if (v == p) continue;
dfs(v, u, d + 1, weight[id]);
sz[u] += sz[v];
}
}
int goUp (int a, int k) {
for (int i = 0; i < 17; i++)
if (k & (1 << i)) a = up[a][i];
return a;
}
int lca (int a, int b) {
if (depth[a] < depth[b]) swap(a, b);
a = goUp(a, depth[a] - depth[b]);
if (a == b) return a;
for (int i = 16; i >= 0; i--)
if (up[a][i] != up[b][i]) a = up[a][i], b = up[b][i];
return up[a][0];
}
int distance (int a, int b) {
return dist[a] + dist[b] - 2 * dist[lca(a, b)];
}
int depthDist (int a, int b) {
return depth[a] + depth[b] - 2 * depth[lca(a, b)];
}
bool check (int p, int u) {
return num[p] <= num[u] && num[u] < num[p] + sz[p];
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
// setup graph
int n, q; cin >> n >> q;
adj.resize(n + 1), weight.resize(n);
fill(all(weight), 1);
for (int i = 1; i < n; i++) {
int a, b; cin >> a >> b;
adj[a].emplace_back(b, i);
adj[b].emplace_back(a, i);
}
// find root
int root = 0;
vector<int> leaves;
for (int i = 1; i <= n; i++)
if (adj[i].size() == 1) root = i, leaves.push_back(i);
// find initial answer
int ans; bool correct; tie(ans, correct) = refineTree(adj, weight, leaves, n, root);
dfs(1, 1, 0, 0);
vector<bool> vis(n + 1);
while (q--) {
int d; cin >> d;
map<int,int> mp;
for (int i = 0; i < d; i++) {
int node; cin >> node;
mp[node]++;
}
if (!correct) mp[root]++;
// create node list for virtual tree
vector<int> qry, nodeList;
for (auto [node, freq] : mp) {
if (!correct && node == root && freq == 1) qry.push_back(node);
else if (adj[node].size() == 1 && freq % 2 == 0) qry.push_back(node);
else if (adj[node].size() > 1 && freq % 2) qry.push_back(node);
}
int sz = qry.size();
for (int u : qry) vis[u] = 1;
sort(all(qry), [&] (int a, int b) { return num[a] < num[b]; });
for (int i = 1; i < sz; i++) {
int tmp = lca(qry[i - 1], qry[i]);
qry.push_back(tmp);
}
sort(all(qry), [&] (int a, int b) { return num[a] < num[b]; });
filter(qry);
for (int i = 0; i < qry.size(); i++) {
if (vis[qry[i]]) nodeList.push_back(i + 1);
vis[qry[i]] = 0;
}
// build virtual tree
vector<vector<pii>> virtTree(qry.size() + 1);
stack<int> st;
vector<int> virtWeight;
for (int i = 0; i < qry.size(); i++) {
while (st.size() && !check(qry[st.top()], qry[i])) st.pop();
if (st.size()) {
int a = st.top() + 1, b = i + 1, c = depthDist(qry[st.top()], qry[i]) - 2 * distance(qry[st.top()], qry[i]), id = virtWeight.size();
virtTree[a].emplace_back(b, id);
virtTree[b].emplace_back(a, id);
virtWeight.push_back(c);
}
st.push(i);
}
// find virtual tree's root
int nroot = 0;
for (int i = 1; i <= qry.size(); i++)
if (virtTree[i].size() <= 1) nroot = i;
int delta; bool curCorrect; tie(delta, curCorrect) = refineTree(virtTree, virtWeight, nodeList, qry.size(), nroot);
int sumEdge = n + d - 1, oneEdge = ans + d + delta;
//cout << "pre ans " << delta << " " << sumEdge << " " << oneEdge << "\n";
if (curCorrect || qry.empty()) cout << 2 * sumEdge - oneEdge << "\n";
else cout << -1 << "\n";
}
return 0;
}
