#include<bits/stdc++.h>
#define ll long long
#define ldb long double
#define fi first
#define se second
#define pir pair<int,int>
using namespace std;
const int maxn = 2e5 + 5;
template <class t1,class t2> inline void maxi(t1 &x,t2 y){if (x < y) x = y;}
template <class t1,class t2> inline void mini(t1 &x,t2 y){if (x > y) x = y;}
struct segment_tree{
int seg[4*maxn];
bool lazy[4*maxn];
void downlazy(int v,int l,int r){
if (!lazy[v]) return;
seg[v] = (r - l + 1) - seg[v];
if (l != r){
lazy[2*v + 1] ^= 1;
lazy[2*v + 2] ^= 1;
}
lazy[v] = 0;
}
void update(int l,int r,int v,int lx,int rx,int val){
downlazy(v,l,r);
if (l > rx || r < lx) return;
if (l >= lx && r <= rx){
lazy[v] ^= val;
downlazy(v,l,r);
return;
}
int w = (l + r)/2;
update(l,w,2*v + 1,lx,rx,val);
update(w + 1,r,2*v + 2,lx,rx,val);
seg[v] = seg[2*v + 1] + seg[2*v + 2];
}
int calc(int l,int r,int v,int lx,int rx){
downlazy(v,l,r);
if (l > rx || r < lx) return 0;
if (l >= lx && r <= rx) return seg[v];
int w = (l + r)/2;
return calc(l,w,2*v + 1,lx,rx) + calc(w + 1,r,2*v + 2,lx,rx);
}
} seg;
vector <int> Q[maxn],vec[maxn];
pir pos[maxn];
int chain[maxn],D[maxn],mx[maxn],father[maxn],deg[maxn];
void input(int n,int q){
for (int i = 1 ; i < n ; i++){
int u,v;
cin >> u >> v;
vec[u].push_back(v);
vec[v].push_back(u);
}
for (int id = 1 ; id <= q ; id++){
int len;
cin >> len;
Q[id].resize(len);
for (int i = 0 ; i < len ; i++) cin >> Q[id][i];
}
}
int get_root(int n){
for (int i = 1 ; i <= n ; i++)
if (vec[i].size() >= 2) return i;
return 1;
}
void dfs(int u,int par){
mx[u] = D[u];
for (int v : vec[u])
if (v != par){
deg[u]++;
D[v] = D[u] + 1;
father[v] = u;
dfs(v,u);
maxi(mx[u],mx[v]);
}
}
void HLD_dfs(int u,int par,bool state,int &m){
pos[u].fi = ++m;
chain[u] = (state) ? u : chain[par];
int nxt = 0;
for (int v : vec[u])
if (v != par && mx[v] == mx[u]){
nxt = v;
break;
}
if (nxt > 0) HLD_dfs(nxt,u,0,m);
for (int v : vec[u])
if (v != par && v != nxt)
HLD_dfs(v,u,1,m);
pos[u].se = m;
}
void HLD_update(int u,int n,int val){
while (D[u] >= 1){
seg.update(1,n,0,pos[chain[u]].fi,pos[u].fi,val);
u = father[chain[u]];
}
}
void prepare(int root,int n){
D[root] = 1;
dfs(root,0);
int m = 0;
HLD_dfs(root,0,1,m);
//prepare leaf
for (int u = 1 ; u <= n ; u++)
if (vec[u].size() == 1)
HLD_update(u,n,1);
}
void add_to_tree(int id,int n){
for (int u : Q[id]){
deg[u]++;
if (deg[u] > 1)
HLD_update(u,n,1);
}
}
void clean_up(int id,int n){
for (int u : Q[id]){
if (deg[u] > 1)
HLD_update(u,n,1);
deg[u]--;
}
}
int get_answer(int root,int id,int n){
add_to_tree(id,n);
int N = Q[id].size() + n;
int parity = seg.calc(1,n,0,pos[root].fi,pos[root].fi);
int cnt = seg.calc(1,n,0,1,n) + Q[id].size();
clean_up(id,n);
if (parity) return -1;
return cnt + 2*(N - 1 - cnt);
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);cout.tie(0);
// freopen("CLEANING.inp","r",stdin);
// freopen("CLEANING.out","w",stdout);
int n,q;
cin >> n >> q;
input(n,q);
int root = get_root(n);
prepare(root,n);
for (int id = 1 ; id <= q ; id++)
cout << get_answer(root,id,n) << "\n";
return 0;
}
