Description：

Solution：

Code：

#include<algorithm>

#include<iostream>

#include<cstdlib>

#include<cstdio>

#include<cmath>

#include<set>

#include<cctype>

#include<cstring>

using namespace std;

inline int rd()

{

	register int res = 0,f = 1;register char c = getchar();

	while(!isdigit(c)){if(c == '-')f = -1;c = getchar();}

	while(isdigit(c))res = (res << 1) + (res << 3) + c - '0',c = getchar();

	return res * f;

}

int n,q;

#define MAXN 300010

struct edge

{

	int to,nxt;

}e[MAXN << 1];

int edgenum = 0;

int lin[MAXN] = {0};

void add(int a,int b)

{

	e[++edgenum] = (edge){b,lin[a]};lin[a] = edgenum;

	e[++edgenum] = (edge){a,lin[b]};lin[b] = edgenum;

}

struct seg

{

	int l,r,id;

	friend bool operator < (const seg &a,const seg &b)

	{

		return a.r < b.r;

	}

};

set<seg> s[MAXN];

int f[MAXN][19],dep[MAXN],siz[MAXN],ind[MAXN],oud[MAXN],tot = 0;

void dfs(int k,int depth)

{

	ind[k] = ++tot;

	dep[k] = depth;siz[k] = 1;

	for(int i = 1;i <= 18;++i)f[k][i] = f[f[k][i - 1]][i - 1];

	for(int i = lin[k];i != 0;i = e[i].nxt)

	{

		if(e[i].to == f[k][0])continue;

		f[e[i].to][0] = k;

		dfs(e[i].to,depth + 1);

		siz[k] += siz[e[i].to];

		s[k].insert((seg){ind[e[i].to],oud[e[i].to],e[i].to});

	}

	oud[k] = ind[k] + siz[k] - 1;

	return;

}

int ski(int a,int depth)

{

	for(int i = 18;i >= 0;--i)if(dep[f[a][i]] >= depth)a = f[a][i];

	return a;

}

int LCA(int a,int b)

{

	if(dep[a] < dep[b])swap(a,b);

	a = ski(a,dep[b]);

	if(a == b)return a;

	for(int i = 18;i >= 0;--i)if(f[a][i] != f[b][i])a = f[a][i],b = f[b][i];

	return f[a][0];

}

int dis(int a,int b)

{

	return dep[a] + dep[b] - 2 * dep[LCA(a,b)];

}

int p[MAXN];

bool vis[MAXN];

int ban[MAXN];

int main()

{

	scanf("%d%d",&n,&q);

	int a,b;

	for(int i = 1;i < n;++i)

	{

		a = rd();b = rd();

		add(a,b);

	}

	dfs(1,1);

	while(q--)

	{

		p[0] = rd();

		for(int i = 1;i <= p[0];++i)p[i] = rd();

		if(p[0] == 1){printf("%d\n",n);continue;}

		int d;

		a = p[1];b = 0;d = -1;

		for(int i = 1;i <= p[0];++i)if(dis(p[i],a) > d)d = dis(p[i],a),b = p[i];

		a = b;b = 0;d = -1;

		for(int i = 1;i <= p[0];++i)if(dis(p[i],a) > d)d = dis(p[i],a),b = p[i];

		if(d % 2 == 1){puts("0");continue;}

		d /= 2;

		int cen = (dep[a] > dep[b] ? ski(a,dep[a] - d) : ski(b,dep[b] - d));

		bool tag = true;

		for(int i = 1;i <= p[0];++i)if(dis(p[i],cen) != d){tag = false;break;}

		if(!tag){puts("0");continue;}

		ban[0] = 0;

		int ans = n;

		for(int i = 1;i <= p[0];++i)

		{

			if(ind[p[i]] < ind[cen] || ind[p[i]] > oud[cen])

			{

				if(!vis[f[cen][0]])

				{

					vis[f[cen][0]] = true;

					ban[++ban[0]] = f[cen][0];

					ans -= (n - siz[cen]);

				}

			}

			else

			{

				int id = s[cen].lower_bound((seg){ind[p[i]],ind[p[i]],p[i]}) -> id;

				if(!vis[id])

				{

					vis[id] = true;

					ban[++ban[0]] = id;

					ans -= siz[id];

				}

			}

		}

		printf("%d\n",ans);

		for(int i = 1;i <= ban[0];++i)vis[ban[i]] = 0;

		ban[0] = 0;

	}

	return 0;

}