#include <bits/stdc++.h>
#define maxn 2005
#define inf 0x3f3f3f3f
using namespace std;
ifstream fin("ubuntzei.in");
ofstream fout("ubuntzei.out");
int n,m;
int k,pr[18];
bool prieten[maxn];
bool viz[maxn];
int aux;
int d[maxn];
vector <pair<int,int> > lista[maxn];
void read()
{
    fin>>n>>m;
    fin>>k;
    for(int i=1;i<=k;i++){
        fin>>pr[i];
        prieten[pr[i]]=1;
    }
    int x,y,c;
    for(int i=1;i<=m;i++)
    {
        fin>>x>>y>>c;
        lista[x].push_back({y,c});
        lista[y].push_back({x,c});
    }
}
struct cmp
{
    bool operator()(int x,int y)
    {
        return d[x]>d[y];
    }
};
int Dijkstra(int start)
{
    priority_queue<int,vector<int>,cmp>  q;
    for(int i=1;i<=n;i++)
        d[i]=inf;
    d[start]=0;
    q.push(start);
    while(!q.empty())
    {
        int nod=q.top();
        q.pop();
        for(auto x:lista[nod])
        {
            int vecin=x.first;
            int cost=x.second;
            if(d[vecin]>d[nod]+cost)
            {
                d[vecin]=d[nod]+cost;
                if(prieten[vecin] && !viz[vecin]){
                    viz[vecin]=1;
                    aux=vecin;
                    return d[vecin];
                }
                q.push(vecin);
            }
        }
    }
    //inseamna ca am ajuns la final si returnam d[n]
    return d[n];
}
bool ok()
{
    for(int i=1;i<=k;i++)
        if(!viz[pr[i]])
            return false;
    return true;
}
int main()
{
    read();
    if(k==0)
    {
        fout<<Dijkstra(1);
        return 0;
    }
    int costTotal=0;
    costTotal+=Dijkstra(1);
    //cout<<aux<<" ";
    while(!ok())
    {
        costTotal+=Dijkstra(aux);
        //cout<<aux<<" ";
    }
    if(aux!=n)
        costTotal+=Dijkstra(aux);
    fout<<costTotal;
    return 0;
}