#pragma GCC optimize("O3")
#include<bits/stdc++.h>
#define ll long long
#define pii pair<int,int>
#define tiii tuple<int,int,int>
using namespace std;
int n;
vector<vector<int>> adj;
vector<int> par;
vector<bool> leaf;
vector<int> dp;
void DFS(int v, int p, vector<int>& dp, vector<int>& arr){
dp[v] = arr[v];
par[v] = p;
if(adj[v].size() == 1 && arr[v] == 0){
dp[v]++;
leaf[v] = true;
}
for(auto u : adj[v]){
if(u == p) continue;
DFS(u,v,dp,arr);
dp[v] += dp[u];
}
}
int solve(int d, int r){
map<int, int> oldDP;
set<int> oldL;
for(int i = 0; i < d; i++){
int a;
cin >> a;
a--;
if(leaf[a]){
leaf[a] = false;
oldL.insert(a);
continue;
}
int node = a;
while(par[node] != node){
if(!oldDP.count(node)){
oldDP[node] = dp[node];
}
dp[node]++;
node = par[node];
}
if(!oldDP.count(node)){
oldDP[node] = dp[node];
}
dp[node]++;
}
int cnt = 0;
for(int i = 0; i < n; i++){
if(dp[i] % 2 == 0){
cnt++;
}
}
int dpr = dp[r];
// we remove the new leafs
for(auto l : oldL){
leaf[l] = true;
}
// reset dp values
for(auto p : oldDP){
dp[p.first] = p.second;
}
if(dpr % 2 == 1){
return -1;
}
return n + d + cnt - 2;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
int q;
cin >> n>> q;
adj.resize(n);
par.resize(n);
for(int i = 0; i < n-1; i++){
int a,b;
cin >> a >> b;
a--;b--;
adj[a].push_back(b);
adj[b].push_back(a);
}
int r = 0;
for(int i = 0; i < n; i++){
if(adj[i].size() > 1){
r = i;
break;
}
}
dp.resize(n);
vector<int> EMPTY(n);
leaf.resize(n);
DFS(r,r,dp,EMPTY);
while(q--){
int d;
cin >> d;
cout << solve(d, r) << "\n";
}
}
