我们可以建立一棵虚树，

然后进行树形 DP 即可。

// Problem: Kingdom and its Cities
// Contest: Luogu
// URL: https://www.luogu.com.cn/problem/CF613D
// Memory Limit: 250 MB
// Time Limit: 2000 ms


#include <bits/stdc++.h>

using namespace std;

const int N = 100010, M = 200010;

struct edge {
	int to, next;
} e[M];

int head[N], idx = 1;

void add(int u, int v) {
	idx++, e[idx].to = v, e[idx].next = head[u], head[u] = idx;
}

int fa[N][25];
int dep[N];
int dfn[N], tot;
int n;

void initgraph() {
	memset(head, 0, sizeof(int) * (n + 10));
	idx = 1;
}

void dfs(int u, int f) {
	fa[u][0] = f;
	dep[u] = dep[f] + 1;
	dfn[u] = ++tot;
	
	for (int i = head[u]; i; i = e[i].next) {
		int to = e[i].to;
		if (to == f) continue;
		dfs(to, u);
	}
}

void initfa() {
	for (int j = 1; j < 25; j++) {
		for (int i = 1; i <= n; i++) {
			fa[i][j] = fa[fa[i][j - 1]][j - 1];
		}
	}
}

int lca(int u, int v) {
	if (dep[u] < dep[v]) swap(u, v);
	
	for (int j = 24; j >= 0; j--) {
		if (dep[fa[u][j]] >= dep[v]) {
			u = fa[u][j];
		}
	}
	
	if (u == v) return u;
	
	for (int j = 24; j >= 0; j--) {
		if (fa[u][j] != fa[v][j]) {
			u = fa[u][j];
			v = fa[v][j];
		}
	}
	
	return fa[u][0];
}

int a[N], cnt;
int sz[N];
int ans;

int stk[N], top;

void buildgraph() {
	sort(a + 1, a + cnt + 1, [](const int x, const int y) { return dfn[x] < dfn[y]; });

	top = 0;
	stk[++top] = 1;
	if (a[1] != 1) stk[++top] = a[1];

	for (int i = 2; i <= cnt; i++) {
		int l = lca(stk[top], a[i]);
		while (top > 1 && dep[stk[top - 1]] >= dep[l]) {
			add(stk[top - 1], stk[top]);
			top--;
		}
		if (stk[top] != l) {
			add(l, stk[top]);
			stk[top] = l;
		}
		stk[++top] = a[i];
	}

	while (top > 1) {
		add(stk[top - 1], stk[top]);
		top--;
	}
}

void dp(int u) {
	if (sz[u]) {
		for (int i = head[u]; i; i = e[i].next) {
			int to = e[i].to;
			dp(to);
			if (sz[to]) ans++;
		}
	}
	else {
		for (int i = head[u]; i; i = e[i].next) {
			int to = e[i].to;
			dp(to);
			sz[u] += sz[to];
		}
		if (sz[u] > 1) {
			ans++;
			sz[u] = 0;
		}
	}
}

void solve() {
	memset(sz, 0, sizeof(int) * (n + 10));
	cin >> cnt;
	for (int i = 1; i <= cnt; i++) {
		cin >> a[i];
		sz[a[i]] = 1;
	}
	for (int i = 1; i <= cnt; i++) {
		if (sz[fa[a[i]][0]]) {
			cout << -1 << '\n';
			return;
		}
	}
	initgraph();
	buildgraph();
	ans = 0;
	dp(1);
	cout << ans << '\n';
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);

	cin >> n;
	for (int i = 1; i < n; i++) {
		int u, v;
		cin >> u >> v;
		add(u, v), add(v, u);
	}
	
	dfs(1, 0);
	initfa();
	
	int T;
	cin >> T;
	while (T--) solve();
	return 0;
}