#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using pi = pair<int,int>;
#define REP(i,n) for (int i = 0; i < n; i++)
#define trav(a,x) for (auto &a : x)
#define all(x) (x).begin(), (x).end()
#define submit(a,b) cout << a << " " << b << endl
#define D(x) //cerr << #x << ": " << x << endl;
const int MAX_N = 2e5;
int n,q;
vector<vi> graph;
vi children;
int total = 0;
int nonleaf = 0;
bool rtr[MAX_N];
bool is_leaf[MAX_N];
int parent[MAX_N];
int calc(int i, int par = -1) {
if (par == -1) total = 0;
parent[i] = par;
int fr = 0;
trav(nei, graph[i]) {
if (nei == par) continue;
int o = calc(nei, i);
total += o; fr += o;
}
fr += children[i]; total += children[i];
if (fr == 0) {fr = 1; is_leaf[i] = 1;}
if (fr > 2) fr = 2 - (fr%2);
rtr[i] = fr == 1;
return fr;
}
void flip(int i, bool rev=false) {
while (i != -1) {
D(i);
if (parent[i] != -1) {
if (rev) children[i]--;
if (is_leaf[i] && children[i] == 0) {
if (!rev) children[i]++;
return;
}
else if (!rtr[i]) total--;
else total++;
if (!rev) children[i]++;
}
D(total);
rtr[i] = !rtr[i];
i = parent[i];
}
}
void make_graph() {
graph.assign(n, vi());
REP(i,n-1) {
int u,v; cin >> u >> v; u--; v--;
graph[u].push_back(v);
graph[v].push_back(u);
}
children.assign(n, 0);
REP(i,n) {
if (graph[i].size() > 1) {nonleaf = i; break;}
}
calc(nonleaf);
D(total);
}
int query() {
int d; cin >> d;
D(d);
vi added;
int prv = total;
REP(dd, d) {
int a; cin >> a; a--;
added.push_back(a);
flip(a);
}
int tot = total;
bool frb = rtr[nonleaf];
trav(a, added) flip(a, 1);
assert(prv == total);
if (frb) return -1;
else return tot+d;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> q;
make_graph();
REP(qq, q) {
cout << query() << "\n";
}
}
