#include <bits/stdc++.h>
#define N 100000
#define pb push_back
#define fu(i, a, b) for (int i = a; i <= b; i++)
#define fd(i, a, b) for (int i = a; i >= b; i--)
#define F first
#define S second
#define ii pair<int, int>
#define M 1000000007
#define int long long
#define el '\n'
#define bit(mark, i) ((mark >> i) & 1)
using namespace std;
int n, q, up[N + 5][20], h[N + 5];
vector <int> g[N + 5];
vector <int> d, e;
void dfs(int u, int p){
int t = 0;
for (auto v : g[u]) if (v != p){
t++;
dfs(v, u);
}
if (t == 0) d.pb(u);
}
void sub1(){
int ans = 1;
bool ok = true;
if (d.size() % 2 == 1){
ok = false;
}
else{
int cap = d.size() / 2;
ans += (cap - 1) * 2;
}
//cout << ans << el;
while (q--){
int m; cin >> m;
fu(i, 1, m){
int x; cin >> x;
}
if (!ok) cout << -1 << el;
else{
cout << ans + m << el;
}
}
}
void dfs1(int u, int p){
for (auto v : g[u]) if (v != p){
h[v] = h[u] + 1;
up[v][0] = u;
dfs1(v, u);
}
}
int lca(int u, int v){
if (h[u] < h[v]) swap(u, v);
int k = h[u] - h[v];
fd(i, 19, 0){
if (bit(k, i)){
u = up[u][i];
}
}
if (u == v) return u;
fd(i, 19, 0){
if (up[u][i] != up[v][i]){
u = up[u][i];
v = up[v][i];
}
}
return up[u][0];
}
int dist(int u, int v, int l){
return h[u] + h[v] - 2 * h[l];
}
map <int, int> mp;
bool cmp(int x, int y){
return h[x] + mp[x] < h[y] + mp[y];
}
int dem[N + 5];
void sub2(){
sort(d.begin(), d.end());
fu(i, 1, q){
int m; cin >> m;
vector <int> a = d;
vector <int> c(m);
int cnt = 0;
fu(i, 1, m){
int x; cin >> x;
auto it = lower_bound(d.begin(), d.end(), x);
if (it == d.end() || *it != x || dem[x]) a.pb(x), mp[x] = 1;
else{
int pos = it - d.begin();
a[pos] = x;
dem[x]++;
}
cnt++;
}
sort(a.begin(), a.end(), cmp);
// for (auto x : a) cout << x << ' ';
// cout << el;
int ans = 0;
if (a.size() % 2 == 1){
cout << -1 << el;
continue;
}
int len = a.size();
int l = lca(a[0], a[len - 1]);
ans += dist(a[0], a[len - 1], l);
// cout << a[0] << ' ' << a[len - 1] << ' ' << l << ' ' << dist(a[0], a[len - 1], l) << el;
for (int i = 1; i < len - 1; i += 2){
int u = a[i], v = a[i + 1];
int l = lca(u, v);
int s = dist(u, v, l);
ans += s;
// cout << u << ' ' << v << ' ' << l << ' ' << s<< el;
}
mp.clear();
memset(dem, 0, sizeof(dem));
// cout << ans << el;
cout << ans + cnt << el;
}
}
signed main(){
// freopen("crt.inp", "r", stdin);
// freopen("crt.out", "w", stdout);
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> q;
vector <int> t;
fu(i, 2, n){
int u, v; cin >> u >> v;
if (u > v) swap(u, v);
g[u].pb(v);
g[v].pb(u);
if (u == 1) t.pb(v);
}
d.pb(1);
dfs(1, 0);
e = d;
sort(e.begin(), e.end());
// for (auto x : d) cout << x << ' ';
// cout << el;
if (t.size() == n - 1){
sub1();
}
dfs1(1, 0);
fu(i, 1, 19){
fu(j, 1, n){
up[j][i] = up[up[j][i - 1]][i - 1];
}
}
sub2();
}
