#include<bits/stdc++.h>

using namespace std;
using ll = long long;

ll n, k;
vector<vector<ll>> adj;
vector<bool> apt, subtree, ans;

void dfs(ll node, ll parent) {
	if (apt[node]) subtree[node] = true;

	for (ll child : adj[node]) {
		if (child == parent) continue;

		dfs(child, node);
		if (subtree[child]) {
			subtree[node] = true;
		}
	}
}

void solve(ll node, ll parent, bool flag) {
	vector<ll> good;
	for (ll child : adj[node]) {
		if (child == parent) continue;

		if (subtree[child]) good.push_back(child);
	}

	if (good.size() > 1) ans[node] = true;
	else if (good.size() == 1 && flag) ans[node] = true;
	else if (apt[node]) ans[node] = true;

	for (ll child : adj[node]) {
		if (child == parent) continue;

		bool child_flag = flag;
		if (good.size() > 1) child_flag = true;
		else if (good.size() == 1 && good[0] != child) child_flag = true;
		else if (apt[node]) child_flag = true;

		solve(child, node, child_flag);
	}
}

signed main() {
	cin >> n >> k;

	adj.resize(n);
	apt.resize(n);
	subtree.resize(n);
	ans.resize(n);

	ll u, v, w;
	for (ll i = 0; i < n - 1; i++) {
		cin >> u >> v >> w;
		u--; v--;
		adj[u].push_back(v);
		adj[v].push_back(u);
	}

	ll a;
	for (ll i = 0; i < k; i++) {
		cin >> a;
		a--;
		apt[a] = true;
	}

	dfs(0, -1);
	solve(0, -1, false);

	ll cnt = 0;
	for (ll i = 0; i < n; i++) {
		if (ans[i]) {
			cnt++;
			// cout << i + 1 << " ";
		}
	}

	cout << cnt << endl;
}