#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;
ll a[N] , b[N] , sz[N];
vector<int> g[N];
int ans = 0;
void go(int v , int p){
sz[v] = 0;
for(int to : g[v]){
if(to != p){
go(to,v);
sz[v] += sz[to];
}
}
while(sz[v] > 2){
sz[v] -= 2;
}
if(sz[v] == 2 && v != 1) ans++;
if(g[v].size() == 1) sz[v] = 1;
}
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);
}
ll res = 0;
for(int i = 1; i <= n+k; i++) res += (g[i].size() == 1);
if(res % 2){
cout << "-1\n";
continue;
}
ans = 0;
go(1,0);
cout << ans+n+k-1 << "\n";
}
}
/*
*/
signed main(){
ios;
solve();
}
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