#include <bits/stdc++.h>
using namespace std;

const int N=1e6+5;

vector <int> g[N];
int fa[N];

void dfs1(int x)
{
	for(auto to:g[x])
		if(to!=fa[x])
			fa[to]=x, dfs1(to);
}

bool need[N], up[N], key[N], col[N];
int ans;

void dfs2(int x)
{
	for(auto to:g[x])
		if(to!=fa[x])
			dfs2(to);

	if(key[x])
	{
		for(auto to:g[x])
			if(to!=fa[x] && need[to])
				ans++;
		return;
	}

	for(auto to:g[x])
		if(to!=fa[x] && need[to])
		{
			up[x]=true, ans++;
			break;
		}

	if(up[x])
		return;

	if(!col[x])
		return;

	need[x]=true;
	for(auto to:g[x])
		if(to!=fa[x] && up[to])
			need[x]=false;
}

int main()
{
	int n,k;
	cin >> n >> k;
	for(int i=1;i<=k;i++)
	{
		int id;
		scanf("%d",&id);
		key[id]=true;
	}

	for(int i=1;i<n;i++)
	{
		int x,y;
		scanf("%d %d",&x,&y);
		g[x].push_back(y);
		g[y].push_back(x);
	}

	for(int i=1;i<=n;i++)
		if(key[i])
			for(auto to:g[i])
				col[to]=true;

	dfs1(1);
	dfs2(1);

	if(need[1])
		ans++;

	printf("%d\n",ans);
	return 0;
}