#include <bits/stdc++.h>

using namespace std;

constexpr int NMax=50005;
constexpr int INF=999999;

ifstream fin("ubuntzei.in");
ofstream fout("ubuntzei.out");

int N,M,K;
vector<int> friends;
vector< pair<int,int> > G[NMax];
int Dist[NMax];
priority_queue< pair<int,int>, vector< pair<int,int> >, greater< pair<int,int> > > Queue;

void Dijkstra(int source)
{
    for(int i=1;i<=N;i++)
        Dist[i]=INF;

    Dist[source]=0;
    Queue.push({Dist[source],source});
    while(!Queue.empty())
    {
        int node=Queue.top().second;
        int d=Queue.top().first;
        Queue.pop();
        if(Dist[node]!=d)
            continue;
        for(auto child : G[node])
        {
            int to=child.first;
            int cost=child.second;
            if(Dist[to]>=Dist[node]+cost)
            {
                Dist[to]=Dist[node]+cost;
                Queue.push({Dist[to],to});
            }
        }
    }
}

int main()
{
    fin>>N>>M>>K;
    for(int i=1;i<=K;i++)
    {
        int x;
        fin>>x;
        friends.push_back(x);
    }
    for(int i=1;i<=M;i++)
    {
        int x,y,z;
        fin>>x>>y>>z;
        G[x].push_back({y,z});
        G[y].push_back({x,z});
    }

    Dijkstra(1);
    if(K==0)
    {
        fout<<Dist[N];
        return 0;
    }

    int dist=0;
    while(!friends.empty())
    {
        int next=friends.back(); friends.pop_back();
        dist+=Dist[next];
        Dijkstra(next);
    }
    dist+=Dist[N];
    fout<<dist;

    return 0;
}