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

#define pb push_back
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define Sz(x) (int)(x).size()
#define bit(x) (1ll << (x))
using ll = long long;
using db = double;
using ull = unsigned long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vii = vector<vi>;
using vl = vector<ll>;
using vll = vector<vl>;
using vs = vector<string>;
using vd = vector<db>;
mt19937 mrand(time(0));

void solve(void)
{
	int n, m;
	cin >> n >> m;
	vii e(n + 2);
	for (int i = 1; i < n; i++)
	{
		int u, v;
		cin >> u >> v;
		e[u].pb(v);
		e[v].pb(u);
	}

	vi a(n + 2);
	for (int i = 1; i <= m; i++)
	{
		int x;
		cin >> x;
		a[x] = 1;
	}

	int ans = 0;
	function<void(int, int, int)> dfs = [&](int u, int fa, int tp)
	{
		
		a[u] |= tp;
		int cnt = 0;
		for (auto v : e[u]) if (v != fa)
			if (a[v] == 0)
				cnt++;

		if (cnt || !a[u]) ans++;
		// cerr << u << " " << cnt << "\n";
		for (auto v : e[u]) if (v != fa)
		{
			cnt -= (a[v] == 0);
			if (cnt >= 1)
				dfs(v, u, 0);
			else
			{
				if (!(a[v] && a[u]))
					dfs(v, u, a[u]);
			}
			cnt += (a[v] == 0);
		}
	};
	dfs(1, 0, 0);
	cout << ans << "\n";
}

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

	// cout << fixed << setprecision(10);

	int T = 1;
	// cin >> T;
	for (int i = 1; i <= T; i++)
	solve();

	return 0;
}