#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;
vi graph[100'001];
int leafs[100'001];
int path0[100'001];
int depth[100'001];
int pre[100'001];
int max_pre[100'001];
int jump[100'001][17];
vi sons[100'001];
int is_change[100'001];
int cur_pre;
int def_ans;
int total_leafs;
int ans;
int dfs(int v, int pop)
{
if(siz(graph[v]) == 1)
{
leafs[v] = 1;
total_leafs++;
}
jump[v][0] = pop;
depth[v] = depth[pop]+1;
pre[v] = cur_pre++;
max_pre[v] = pre[v];
forall(it,graph[v])
{
if(it != pop)
{
leafs[v] += dfs(it,v);
leafs[v] %= 2;
max_pre[v] = max_pre[it];
}
}
if(leafs[v] == 0 && v != pop)
{
path0[v] = 1;
def_ans++;
}
return leafs[v];
}
void dfspath(int v, int pop)
{
path0[v] += path0[pop];
forall(it,graph[v])
{
if(it != pop)
{
dfspath(it,v);
}
}
}
int lca(int a, int b)
{
if(pre[a] <= pre[b] && max_pre[a] >= pre[b]) return a;
for(int bit = 16; bit >= 0; bit--)
{
if(max_pre[jump[a][bit]] < pre[b] || pre[jump[a][bit]] > pre[b])
{
a = jump[a][bit];
}
}
return jump[a][0];
}
int dfs_ans(int v, int pop)
{
int h = is_change[v];
forall(it,sons[v])
{
h += dfs_ans(it,v);
}
if(h % 2 == 1)
{
int len = depth[v] - depth[pop];
int zero = path0[v] - path0[pop];
ans += len - 2*zero;
}
return h;
}
int main()
{
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//random_start();
int n,q;
cin >> n >> q;
rep(i,n-1)
{
int a,b;
cin >> a >> b;
graph[a].pb(b);
graph[b].pb(a);
}
int root = 1;
rep2(i,1,n) if(siz(graph[i]) == 1) root = i;
dfs(root,root);
dfspath(root,root);
rep2(bit,1,16)
{
rep2(i,1,n)
{
jump[i][bit] = jump[jump[i][bit-1]][bit-1];
}
}
unordered_map<int,int> new_tree;
vector<pii> verts_pom;
set<pii> new_sons;
rep(qq,q)
{
int d;
cin >> d;
new_tree = {};
rep(j,d)
{
int x;
cin >> x;
new_tree[x]++;
}
ans = n-1+d+def_ans;
int not_l = 0l;
verts_pom = {};
forall(it,new_tree)
{
if(siz(graph[it.ff]) == 1)
{
new_tree[it.ff]--;
not_l++;
}
if(new_tree[it.ff] % 2 == 1) verts_pom.pb({pre[it.ff],it.ff});
}
sort(all(verts_pom));
if((total_leafs + d - not_l) % 2 == 1)
{
cout << "-1\n";
continue;
}
if(siz(verts_pom) == 0)
{
cout << ans << "\n";
continue;
}
new_tree = {};
forall(it,verts_pom) new_tree[it.ss] = 1;
int prev = -1;
forall(it,verts_pom)
{
is_change[it.ss] = 1;
if(prev != -1)
{
new_tree[lca(prev,it.ss)] = 1;
}
prev = it.ss;
}
new_tree[lca(verts_pom[0].ss,prev)] = 1;
verts_pom = {};
forall(it,new_tree) verts_pom.pb({-depth[it.ff],it.ff});
sort(all(verts_pom));
int root2 = 0;
new_sons = {};
forall(it,verts_pom)
{
auto ptr = new_sons.lower_bound({pre[it.ss],-1});
root2 = it.ss;
while(ptr != new_sons.end())
{
if((*ptr).ff <= max_pre[it.ss])
{
sons[it.ss].pb((*ptr).ss);
new_sons.erase(ptr);
ptr = new_sons.lower_bound({pre[it.ss],-1});
}
else
{
break;
}
}
new_sons.insert({pre[it.ss],it.ss});
}
dfs_ans(root2,root);
cout << ans << "\n";
forall(it,verts_pom)
{
is_change[it.ss] = 0;
sons[it.ss] = {};
}
}
}
