#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
using pii = pair<int, i64>;

const int maxn = 300005;

int n, m;
int h[maxn], e[maxn * 2], ne[maxn * 2], w[maxn * 2], idx;
int army[maxn], fa[maxn][20];
i64 dist[maxn][20];
int vis[maxn], dp[maxn];
std::vector<i64> rest[maxn];

void add(int a, int b, int c) {
	e[idx] = b, ne[idx] = h[a], w[idx] = c, h[a] = idx ++;
}

void dfs(int u) {
	for (int j = 1; j <= __lg(n); j ++) {
		dist[u][j] = dist[u][j - 1] + dist[fa[u][j - 1]][j - 1];
		fa[u][j] = fa[fa[u][j - 1]][j - 1];
	}
	for (int i = h[u]; ~i; i = ne[i]) {
		int v = e[i];
		if (v == fa[u][0]) continue;
		dist[v][0] = w[i], fa[v][0] = u;
		dfs(v);
	}
}

int main() {
	cin.tie(0);
	cout.tie(0);
	ios::sync_with_stdio(0);

	cin >> n;

	memset(h, -1, sizeof h);
	for (int i = 1; i < n; i ++) {
		int a, b, c;
		cin >> a >> b >> c;
		add(a, b, c);
		add(b, a, c);
	}

	cin >> m;
	for (int i = 1; i <= m; i ++)
		cin >> army[i];

	dfs(1);

	i64 lo = 0, ro = 1e18;
	while (lo <= ro) {
		i64 mid = lo + ro >> 1;

		memset(vis, 0, sizeof vis);
		memset(dp, 0, sizeof dp);
		for (int i = 1; i <= n; i ++)
			rest[i].clear();

		for (int i = 1; i <= m; i ++) {
			int u = army[i];
			i64 tot = mid;
			for (int j = __lg(n); j >= 0; j -- )
				if (fa[u][j] > 1 && dist[u][j] <= tot)
					tot -= dist[u][j], u = fa[u][j];
			vis[u] = 1;
			if (fa[u][0] == 1) rest[u].push_back(tot);
		}

		memset(dp, 0, sizeof dp);
		std::multiset<i64> usable;
		for (int i = h[1]; ~i; i = ne[i]) {
			int rt = e[i];
			auto dfs = [&](auto dfs, int u) -> void {
				if (u != rt) dp[u] = vis[u];
				for (int i = h[u]; ~i; i = ne[i]) {
					int v = e[i];
					if (v == fa[u][0]) continue;
					dfs(dfs, v);
					dp[u] |= dp[v];
				}
			};

			sort(rest[rt].begin(), rest[rt].end(), greater<int>());
			if (!dp[rt]) {
				if (rest[rt].size()) {
					dp[rt] = 1;
					rest[rt].pop_back();
				}
			}
			for (auto t : rest[rt])
				usable.insert(t - w[i]);
		}

		bool ok = true;
		for (int i = h[1]; ~i; i = ne[i]) {
			int u = e[i];
			if (!dp[u]) {
				auto it = usable.lower_bound(w[i]);
				if (it == usable.end()) {
					ok = false;
					break;
				}
				usable.erase(it);
			}
		}

		if (ok) ro = mid - 1;
		else lo = mid + 1;
	}

	cout << ro + 1 << endl;

	return 0;
}