/*DEP TRAI CO J SAI*/
/* %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%@@@@@@%%##***************************+++++++++++++++++++++++++++++++++++++++++++++++***************************######%%%@%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*
Template header: dùng cho mọi code C++ theo yêu cầu.
*/
#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize ("O3")
#pragma GCC optimize ("unroll-loops")
#define fi first
#define se second
#define pu emplace_back
#define ll long long
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, Q;
if(!(cin >> n >> Q)) return 0;
vector<int> deg(n+1, 0);
for(int i=0;i<n-1;i++){
int u,v; cin>>u>>v;
deg[u]++; deg[v]++;
}
// For each query: read Di and then Di integers (attachment nodes)
for(int qi=0; qi<Q; qi++){
int Di; cin>>Di;
vector<int> addList(Di);
for(int i=0;i<Di;i++) cin>>addList[i];
// compute degrees after additions
bool ok = true;
// we can update by counting freq
unordered_map<int,int> freq;
freq.reserve(Di*2+10);
for(int x: addList) freq[x]++;
for(auto &p: freq){
int node = p.first;
// Note: node in range 1..n
}
// check all vertices 1..n
for(int v=1; v<=n; v++){
int newdeg = deg[v] + (freq.count(v) ? freq[v] : 0);
if(newdeg > 1 && (newdeg % 2 == 1)){
ok = false; break;
}
}
if(!ok) cout << -1 << '\n';
else cout << ( (n-1) + Di ) << '\n';
}
return 0;
}
