#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fti(i, x, y) for (int i = x; i <= y; ++i)
#define F first
#define S second
const int MA = 1e5 + 10;
int n, q, in[MA], D[MA], dp[MA];
bool leaf[MA], s1 = 1;
vector <int> c[MA], con[MA], con1[MA];
void sub1()
{
int leaves = n - 1;
fti(Q, 1, q)
{
unordered_map <int, int> mp;
int cnt = leaves, res = n - 1;
for (int x : c[Q])
{
++mp[x]; if (mp[x] > 1) ++cnt;
}
if (cnt & 1)
{
cout << -1 << '\n'; continue;
}
res = n + D[Q] - 1;
for (auto x : mp)
{
int f = x.S;
res += (f - 1) % 2;
}
cout << res << '\n';
}
}
int sz[MA];
void dfs(ll u, ll p)
{
dp[u] = leaf[u];
for (int v : con1[u])
{
if (v == p) continue;
dfs(v, u); dp[u] += (dp[v] - 1) % 2;
}
}
void sub2()
{
int root = 0;
fti(i, 1, n)
if (!leaf[i])
{
root = i; break;
}
fti(Q, 1, q)
{
int cnt = accumulate(leaf + 1, leaf + n + 1, 0);
ll nd = n;
fti(i, 1, n) con1[i].clear();
fti(i, 1, n)
for (int x : con[i]) con1[i].push_back(x);
unordered_map <int, int> mp;
for (int x : c[Q])
{
con1[++nd].push_back(x);
con1[x].push_back(nd);
if (mp[x] > 1) ++cnt;
}
if (cnt & 1)
{
cout << -1 << '\n'; continue;
}
fti(i, 1, n + D[Q]) dp[i] = 0;
dfs(root, 0);
cout << dp[root] << '\n';
}
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> q;
fti(i, 1, n - 1)
{
int u, v; cin >> u >> v;
++in[u], ++in[v];
con[u].push_back(v);
con[v].push_back(u);
}
fti(i, 1, q)
{
cin >> D[i];
fti(j, 1, D[i])
{
int x; cin >> x; c[i].push_back(x);
s1 &= (x != 1);
}
}
fti(i, 1, n) leaf[i] = (in[i] == 1);
// cerr << accumulate(leaf + 1, leaf + n + 1, 0);
if (s1 && in[1] == n - 1)
sub1();
// else
// sub2();
return 0;
}
/**
5 3
1 2
1 3
1 4
1 5
9 3 3 4 4 4 5 5 5 5
7 2 2 3 3 3 5 5
2 2 2
7 3
1 2
2 4
4 5
5 6
5 7
3 4
1 4
2 2 4
1 1
7 3
1 2
2 4
4 5
5 6
5 7
3 4
4 1 1 2 6
3 6 6 2
2 2 7
*/
