fdasfsa

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

const int maxNum = 100000;
const int maxCost = 1 << 30;

ll numCities, numImportant;
bool important[maxNum];
vector<pair<ll, ll> > graph[maxNum];

pair<ll, ll> solve(ll current, ll previous){
    ll maxSum = 0, cost = 0, sum = 0;
    for (ll i = 0; i < graph[current].size(); i++){
        ll  next = graph[current][i].first;
        ll distance = graph[current][i].second;

        if (next == previous){
            continue;
        }

        pair<ll, ll> curr = solve(next, current);
        maxSum = max(maxSum, min(distance, curr.first));
        sum += min(distance, curr.first);
        cost += curr.second;
    }

    if (important[current]){
        cost += sum;
        maxSum = maxCost;
    }

    else{
        cost += sum - maxSum;
    }

    return make_pair(maxSum, cost);
}

int main(){
    cin >> numCities >> numImportant;
    for (ll i = 1; i < numCities; i++){
        ll from_city, to_city, cost;
        cin >> from_city >> to_city >> cost;

        graph[from_city].push_back(make_pair(to_city, cost));
        graph[to_city].push_back(make_pair(from_city, cost));
    }

    memset(important, false, sizeof(important));
    for (ll i = 0; i < numImportant; i++){
        ll city;
        cin >> city;
        important[city] = true;
    }

    cout << solve(0, -1).second << endl;
    return 0;
}