#include <bits/stdc++.h>
using namespace std;
#define dbg(x) "[" #x " = " << (x) << "]"
const int MAX = 1e5 + 5;
int n, q, timerHLD, root, parent[MAX], heavy[MAX], sz[MAX], depth[MAX], head[MAX], posHLD[MAX];
vector<int> adj[MAX];
bool original_is_leaf[MAX], is_leaf[MAX];
void predfs(int u, int pre){
sz[u] = 1;
for(int v : adj[u]) if(v != pre){
depth[v] = depth[u] + 1;
parent[v] = u;
predfs(v, u);
sz[u] += sz[v];
if(heavy[u] == 0 || sz[heavy[u]] < sz[v]){
heavy[u] = v;
}
}
}
void dfsHLD(int u, int hd){
head[u] = hd;
posHLD[u] = ++timerHLD;
if(heavy[u] != 0){
dfsHLD(heavy[u], hd);
for(int v : adj[u]){
if(v != parent[u] && v != heavy[u]){
dfsHLD(v, v);
}
}
}
}
struct SegmentTree{
vector<int> st, lazy;
SegmentTree(int n) : st(n << 2), lazy(n << 2) {}
void build(int id, int l, int r){
st[id] = r - l + 1;
if(l < r){
int mid = l + r >> 1;
build(id << 1, l, mid);
build(id << 1 | 1, mid + 1, r);
st[id] = st[id << 1] + st[id << 1 | 1];
}
}
void flip(int id, int l, int r){
st[id] = (r - l + 1) - st[id];
lazy[id] ^= 1;
}
void lazyDown(int id, int l, int r, int mid){
if(lazy[id] > 0){
flip(id << 1, l, mid);
flip(id << 1 | 1, mid + 1, r);
lazy[id] = 0;
}
}
void pull(int id){
st[id] = st[id << 1] + st[id << 1 | 1];
}
void update(int id, int l, int r, int u, int v){
if(u <= l && r <= v){
flip(id, l, r);
} else{
int mid = l + r >> 1;
lazyDown(id, l, r, mid);
if(u <= mid) update(id << 1, l, mid, u, v);
if(mid < v) update(id << 1 | 1, mid + 1, r, u, v);
pull(id);
}
}
int getFilled(){
return st[1];
}
};
void toggle(int u, SegmentTree& T){
while(u > 0){
T.update(1, 1, n, posHLD[head[u]], posHLD[u]);
u = parent[head[u]];
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
#define filename "task"
if(fopen(filename".inp", "r")){
freopen(filename".inp", "r", stdin);
freopen(filename".out", "w", stdout);
}
cin >> n >> q;
for(int i = 1; i < n; ++i){
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
for(int i = 1; i <= n; ++i){
if((int)adj[i].size() > 1){
root = i;
break;
}
}
predfs(root, -1);
dfsHLD(root, root);
SegmentTree T(n);
T.build(1, 1, n);
int numLeaves = 0;
for(int i = 1; i <= n; ++i){
if((int)adj[i].size() == 1){
original_is_leaf[i] = true;
++numLeaves;
toggle(i, T);
}
}
copy(original_is_leaf + 1, original_is_leaf + 1 + n, is_leaf + 1);
int original_numLeaves = numLeaves;
while(q--){
vector<int> roll;
int D;
cin >> D;
vector<int> nodes(D);
for(int i = 0; i < D; ++i){
cin >> nodes[i];
if(is_leaf[nodes[i]]){
is_leaf[nodes[i]] = false;
} else{
toggle(nodes[i], T);
++numLeaves;
roll.push_back(nodes[i]);
}
}
if(numLeaves & 1){
cout << -1 << '\n';
} else{
cout << n + D + T.getFilled() - 2 << '\n';
}
numLeaves = original_numLeaves;
for(int u : nodes){
is_leaf[u] = original_is_leaf[u];
}
while(!roll.empty()){
toggle(roll.back(), T);
roll.pop_back();
}
}
}
