#include <bits/stdc++.h>
using namespace std;
vector<pair<int,int> > G[100500];
vector<int> exits;
int n, m, k;
int dijkstra(int at)
{
    priority_queue<pair<int,int> > pq;
    pq.push(make_pair(0,at));
    vector<int> dist;
    dist.resize(n);
    for(int i=0;i<n;i++)
        dist[i] = 1e9;
    bool vis[n][2];
    memset(vis,false,sizeof(vis));
    for(int i=0;i<exits.size();i++)
        vis[exits[i]][0] = true;
    dist[0] = 0;
    while(!pq.empty())
    {
        pair<int,int> state = pq.top();
        pq.pop();
        int city = state.second;
        int path = -state.first;
        if(city == 0 && vis[city][0] == true)
            break;
        if(vis[city][0] == false)
        {
            cout<<city<<" "<<path<<endl;
            vis[city][0] = true;
            vector<pair<int,int> > can_go = G[city];
            for(int i=0;i<can_go.size();i++)
            {
                int next = can_go[i].first;
                int dist_between = can_go[i].second;
                if(dist[next] > dist[city] + dist_between && vis[next][0] == false)
                {
                    dist[next] = dist[city] + dist_between;
                    pq.push(make_pair(-dist[next], next));
                }
                else if(vis[next][0] == true)
                    dist[next] = dist[city] + dist_between;
            }
        }
        if(vis[city][1] == false)
            continue;
    }
    int naj = -1;
    int sec_naj = -1;
    for(int i=0;i<exits.size();i++)
    {
        if(dist[exits[i]] >= naj)
        {
            sec_naj = naj;
            naj = dist[exits[i]];
        }
    }
        return sec_naj;
}
int main()
{

    cin>>n>>m>>k;
    for(int i=0;i<m;i++)
    {
        int from, to, weigh;
        cin>>from>>to>>weigh;
        G[from].push_back(make_pair(to,weigh));
        G[to].push_back(make_pair(from,weigh));
    }

    for(int i=0;i<k;i++)
    {
        int a;
        cin>>a;
        exits.push_back(a);
    }
    cout<<dijkstra(0)<<endl;
    return 0;
}