#include <iostream>
#include <fstream>
#include <queue>
#include <vector>
#include <limits.h>
#define INF INT_MAX
#define NMAX 250001
///DIJKSTRA.
using namespace std;
ifstream f("ubuntzei.in");
ofstream g("ubuntzei.out");
int n,m,a,b,c,D[NMAX],i,k,v[2001],OK,Lungime,fr[2001];
vector < pair < int,int > > G[NMAX];
struct Conditie
{
    bool operator()(int x,int y)
    {
        return D[x] > D[y];
    }
};
priority_queue < int, vector < int > , Conditie > q;
void Citire()
{
    f>>n;
    f>>m;
    f>>k;
    for(i=1;i<=k;i++)
    {
        f>>v[i];
        fr[v[i]]=1;
    }
    for(i=1;i<=m;i++)
    {
        f>>a;
        f>>b;
        f>>c;
        G[a].push_back(make_pair(b,c));
        G[b].push_back(make_pair(a,c));
    }
}
void Rezolvare(int Start)
{
    int Cost,Vecin,Curent,minim;
    bool Incoada[NMAX];
    for(i=1;i<=n;i++)
        D[i]=INF;
    D[Start]=0;
    q.push(Start);
    Incoada[Start]=true;
    while(!q.empty())
    {
        Curent=q.top();
        q.pop();
        Incoada[Curent]=false;
        for(unsigned int i=0;i<G[Curent].size();i++)
        {
            Vecin=G[Curent][i].first;
            Cost=G[Curent][i].second;
            if(D[Vecin]>D[Curent]+Cost)
            {
                D[Vecin]=D[Curent]+Cost;
                if(Incoada[Vecin]==false)
                {
                    q.push(Vecin);
                    Incoada[Vecin]=true;
                }
            }
        }
    }
    int mini=99999999,t;
    for(i=1;i<=k;i++)
    {
        if(D[v[i]]<=mini&&fr[v[i]]==1)
        {
            mini=D[v[i]];
            t=v[i];
        }
    }
    if(mini!=99999999)
    {
        Lungime=Lungime+mini;
        fr[t]=0;
        Rezolvare(t);
    }
    else
    {
        Lungime=Lungime+D[n];
    }
}
void Afisare()
{
    g<<Lungime;
}
int main()
{
    Citire();
    Rezolvare(1);
    Afisare();

    return 0;
}