/****ThanhCodeDao*****/
/*******Azazel*******/
#include<bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define pb push_back
#define checkbit(mask,i) ((mask>>i)&1)
#define bit(i) (1<<i)
#define MLog 21
#define all(v) v.begin(), v.end()
#define uni(v) v.erase(unique(all(v)), v.end())
typedef long long ll;
const ll maxN = 2e5+366, modd = 1e9+7;
struct Point {
ll x,y;
};
ll cross(Point p,Point q,Point r) { // vi tri r voi duong pq >0 la ben trai, =0 la thang hang
ll val = (q.x-p.x)*(r.y-q.y) - (q.y-p.y)*(r.x-q.x);
if(val < 0) return -1;
if(val > 0) return 1;
return 0;
}
ll dot(Point vecA,Point vecB) { // tra ve >0 la nhon, <0 la tu, =0 la vuong, 2 vecto phai chung goc
ll val = vecA.x*vecB.x + vecA.y*vecB.y;
if(val < 0) return -1;
if(val > 0) return 1;
return 0;
}
double triarea(Point p,Point q,Point r) { // cross(pq * pr) / 2
double cross = (q.x-p.x)*(r.y-q.y) - (q.y-p.y)*(r.x-q.x);
return fabs(cross)/2.0;
}
/* de cho
*/
/* nhan xet nho
*/
/* nhan xet tu thuat trau
*/
int n,q;
int root = -1;
int cntleaf = 0;
vector<int> adj[maxN];
vector<int> tree[maxN];
int up[maxN], dp[maxN];
void dfs(int u,int par) {
if(adj[u].size() == 1) {
up[u] = 1;
dp[u] = 1;
return;
}
for(int v : adj[u]) {
if(v==par) continue;
dfs(v,u);
up[u] += up[v];
dp[u] += dp[v];
}
up[u] %= 2;
if(up[u] == 0) up[u] = 2;
if(par != 0) dp[u] += up[u];
}
vector<int> vertex;
void reset() {
for(int u : vertex) {
adj[u].pop_back();
}
vertex.clear();
cntleaf = 0;
}
void sub12() {
while(q--) {
int d;
cin >> d;
int all = n;
for(int i = 1; i<=d; i++) {
int u;
cin >> u;
++all;
adj[u].pb(all);
adj[all].pb(u);
vertex.pb(u);
vertex.pb(all);
}
for(int i = 1; i<=all; i++) {
cntleaf += (adj[i].size() == 1);
if(adj[i].size() != 1) root = i;
}
if(cntleaf%2) {
cout << -1 << '\n';
reset();
continue;
}
dfs(root,0);
cout << dp[root] << '\n';
for(int i = 1; i<=all; i++) {
dp[i] = up[i] = 0;
}
reset();
}
}
int is_leaf[maxN];
int exist[maxN];
int sz[maxN],depth[maxN], chainHead[maxN], chainId[maxN], cntPos = 0, cntChain = 1, a[maxN], pos[maxN];
int parent[maxN];
pair<int,int> st[maxN*4];
// F la cnt1, S la cnt2
int lz[maxN*4];
void build(int id,int l,int r) {
if(l==r){
st[id].F = (up[a[l]]%2 == 1); // dinh o vi tri nay trong hld
st[id].S = (up[a[l]]%2 == 0);
return;
}
int mid = (l+r)/2;
build(2*id,l,mid);
build(2*id+1,mid+1,r);
st[id].F = st[id*2].F + st[id*2+1].F;
st[id].S = st[id*2].S + st[id*2+1].S;
}
void push(int id){
if(lz[id]){
lz[id*2] ^= lz[id];
lz[id*2+1] ^= lz[id];
swap(st[id*2].F, st[id*2].S);
swap(st[id*2+1].F, st[id*2+1].S);
lz[id] = 0;
}
}
void uplz(int id,int l,int r,int u,int v) {
if(v < l || r < u || l > r) return;
if(u<=l and r<=v){
swap(st[id].F, st[id].S);
lz[id] ^= 1;
return;
}
int mid = (l+r)/2;
push(id);
uplz(2*id,l,mid,u,v);
uplz(2*id+1,mid+1,r,u,v);
st[id].F = st[id*2].F + st[id*2+1].F;
st[id].S = st[id*2].S + st[id*2+1].S;
}
int get(int id,int l,int r,int u,int v){
if(v < l || r < u || l > r) return 0;
if(u<=l and r<=v) return st[id].F;
push(id);
int mid = (l+r)/2;
return get(2*id,l,mid,u,v) + get(2*id+1,mid+1,r,u,v);
}
void pre_dfs(int u,int par){
sz[u] = 1;
parent[u] = par;
for(int v : adj[u]){
if(v==par) continue;
pre_dfs(v,u);
sz[u] += sz[v];
depth[v] = depth[u] + 1;
}
}
void hld(int u,int par){
if(chainHead[cntChain] == 0){
chainHead[cntChain] = u;
}
chainId[u] = cntChain;
a[++cntPos] = u;
pos[u] = cntPos;
int bigchild = 0;
for(int v : adj[u]){
if(v==par) continue;
if(sz[v] > sz[bigchild]) bigchild = v;
}
if(bigchild){
hld(bigchild, u);
}
for(int v : adj[u]){
if(v==par or v==bigchild) continue;
++cntChain;
hld(v,u);
}
}
void upHld(int u,int v){
int baseu = u, basev = v;
while(chainId[u] != chainId[v]){
// cout << 'r' << '\n';
if(depth[chainHead[chainId[u]]] < depth[chainHead[chainId[v]]]) swap(u,v); // u sau hon v
uplz(1,1,n,pos[ chainHead[chainId[u] ] ], pos[u]);
u = parent[chainHead[chainId[u]]];
}
if(pos[u] > pos[v]) swap(u,v);
uplz(1,1,n,pos[u],pos[v]);
}
void sub34() {
for(int i = 1; i<=n; i++) {
if(adj[i].size() == 1) is_leaf[i] = 1;
if(adj[i].size() != 1) root = i;
cntleaf += is_leaf[i];
}
dfs(root,0);
pre_dfs(root,0);
hld(root,0);
build(1,1,n);
// cout << get(1,1,n,pos[3],pos[3]);
while(q--) {
int d;
cin >> d;
vector<int> vertex, realup;
int new_cntleaf = cntleaf;
int ans = d;
for(int i = 1; i<=d; i++) {
int u;
cin >> u;
vertex.pb(u);
if(is_leaf[u] and exist[u] == 0) {
exist[u] = 1;
} else {
++new_cntleaf;
realup.pb(u);
}
}
if(new_cntleaf%2) {
cout << -1 << '\n';
} else {
// update u len root
for(int u : realup){
upHld(root, u);
}
int cnt1 = get(1,1,n,1,n);
int cnt2 = n - cnt1;
int state_root = get(1,1,n,pos[root],pos[root]);
cnt1 -= (state_root == 1);
cnt2 -= (state_root == 0);
ans = ans + cnt1 + cnt2*2;
cout << ans << '\n';
for(int u : realup){
upHld(root,u); // dao nguoc truy van
}
}
// reset
for(int u : vertex) {
exist[u] = 0;
}
}
}
void solve() {
cin >> n >> q;
for(int i = 1; i<=n-1; i++) {
int u,v;
cin >> u >> v;
adj[u].pb(v);
adj[v].pb(u);
}
// sub12();
sub34();
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
// freopen("inp.txt","r",stdin);
//freopen("out.txt","w",stdout);
solve();
return 0;
}
/* simple solution */
/* simple code */
//base
