#include <iostream>
using namespace std;
typedef long long ll;
const int maxn = 1e5 + 10;
const ll INF = 1e18;
int n, k;
vector<pair<int, int> > graph[maxn];
bool pay_toll[maxn];

pair<ll, ll> dfs(int node, int parent) {
    ll res = 0, sum = 0, max_edge = 0;
    for(int i = 0; i < (int) graph[node].size(); i++) {
        int neighbour = graph[node][i].first;
        if(neighbour != parent) {
            ll weight = graph[node][i].second;
            pair<ll, ll> p = dfs(neighbour, node);
            res += p.first;
            sum += min(weight, p.second);
            max_edge = max(max_edge, min(weight, p.second));
        }
    }
    if(pay_toll[node]) {
        res += sum;
        max_edge = INF;
    }
    else {
        res += sum - max_edge;
    }
    return make_pair(res, max_edge);
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin >> n >> k;

    for(int i = 1; i < n; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        graph[a].push_back(make_pair(b, c));
        graph[b].push_back(make_pair(a, c));
    }
    for(int i = 0; i < maxn; i++) {
        pay_toll[i] = false;
    }

    for(int i = 0; i < k; i++) {
        int x;
        cin >> x;
        pay_toll[x] = true;
    }
    cout << dfs(0, -1).first << endl;
    return 0;
}