#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define in insert
#define lb lower_bound
#define F first
#define S second
#define sz size()
#define int long long
#define all(v) v.begin(),v.end()
#define FOR1(x, n) for(int j = x; j <= n; j ++)
#define FOR(x, n, m, d) for(int x = n; x <= m; x += d)
#define FORR(x, n, m, d) for(int x = n; x >= m; x -= d)
#define nikita ios_base::sync_with_stdio(0), cin.tie(0);
const int N = 3e6+5, M = 210;
int a[N], b[N], pref[N], d[N], c[N], tin[N], timer = 0, tout[N], t[N];
int n,m,k,sum=0,x,y, ans, r, cnt, l,inf = -1e18, dist[N];
string s, str;
vector<int>g[N];
bool f = 0;
void dfs(int v, int p = 0){
tin[v] = ++timer;
for(auto i : g[v]){
if(i != p)dfs(i, v);
}
sum = 0;
for(auto i : g[v]){
if(i != p)sum += d[i];
}
ans += sum;
if(sum % 2 || g[v].sz == 1)d[v] = 1;
else d[v] = 2;
tout[v] = timer;
}
void sol(int v, int p = 0){
if(v!=1){
dist[v] = dist[p]+1;
c[v] = c[p] + (d[v] == 2);
}
for(auto i : g[v]){
if(i != p)sol(i, v);
}
}
void upd(int pos, int v = 1, int tl = 1, int tr = n){
if(tl==tr){
t[v] ++;
return;
}
int tm = (tl + tr) >> 1;
if(pos <= tm)upd(pos, v*2, tl, tm);
else upd(pos, v*2+1, tm+1, tr);
t[v] = t[v*2] + t[v*2+1];
}
int get(int l, int r, int v = 1, int tl = 1, int tr = n){
if(l > tr || tl > r)return 0;
if(l <= tl && tr <= r)return t[v];
int tm = (tl + tr) >> 1;
return get(l, r, v*2, tl, tm) + get(l, r, v*2+1, tm+1, tr);
}
void clear(int v = 1, int tl = 1, int tr = n){
t[v] = 0;
int tm = (tl + tr) >> 1;
if(t[v*2])clear(v*2, tl, tm);
if(t[v*2+1])clear(v*2+1, tm+1, tr);
if(tl == tr)return;
}
void solve(){
cin >> n >> m;
FOR(i, 2, n, 1){
cin >> x >> y;
g[x].pb(y), g[y].pb(x);
}
int lp = 0;
FOR(i, 1, n, 1)lp += (g[i].sz==1);
sum = 0;
dfs(1);
sol(1);
FOR(i, 1, m, 1){
cin >> k;
int ko = 0;
sum = 0;
vector<pair<int, int>>v;
FOR(j, 1, k, 1){
cin >> x;
v.pb({dist[x], x});
}
sort(all(v));
reverse(all(v));
FOR(j, 0, k-1, 1){
x = v[j].S;
if(g[x].sz == 1 && !pref[x])ko ++, sum ++, pref[x] = 1;
else{
sum++;
int op = get(tin[x], tout[x]);
sum += (dist[x] - c[x] - c[x]) * (op % 2 ? -1 : 1);
upd(tin[x]);
}
}
FOR(j, 0, k-1, 1)pref[v[j].S] = 0;
clear();
if((k + lp - ko) % 2){cout << "-1\n";continue;}
cout << ans + sum << '\n';
}
}
signed main() {
nikita
int tt = 1;
if(!tt)cin >> tt;
FOR(i, 1, tt, 1) {
solve();
}
}
