#include <fstream>
#include <vector>
#include <queue>
#include <algorithm>
#define NMax 2002
#define INF 1<<30
using namespace std;
ifstream fin("ubuntzei.in");
ofstream fout("ubuntzei.out");
std::vector< std::pair<int,int> > G[NMax],GP[NMax];
std::vector<int> A,B,XD[NMax];
std::queue< std::pair<int,int> > coada;
int n,m,k,x,y,cost,d[NMax],CF[NMax][20],Maxim,contor;
bool viz[NMax];
void dijkstra(int x0)
{
    fill(d+1,d+n+1,INF);
    d[x0] = 0;
    coada.push(std::make_pair(x0,0));
    while(!coada.empty())
    {
        int nod = (coada.front()).first;
        int val = (coada.front()).second;
        coada.pop();
        for(int i=0;i<G[nod].size();++i)
        {
            if(d[G[nod][i].first] > val + G[nod][i].second)
            {
                d[G[nod][i].first] = val + G[nod][i].second;
                coada.push(std::make_pair(G[nod][i].first,d[G[nod][i].first]));
            }
        }
    }
}

void DFS(int x0)
{
    viz[x0] = true;
    contor++;
    if(contor==k+2&&x0==n&&cost<Maxim)Maxim = cost;
    for(int i=0;i<GP[x0].size();++i)
    {
        if(!viz[GP[x0][i].first])
        {
            cost = cost + GP[x0][i].second;
            DFS(GP[x0][i].first);
            cost = cost - GP[x0][i].second;
        }
    }
    viz[x0] = false;
}

int main()
{
    Maxim = INF;
    fin>>n>>m>>k;
    for(int i=1;i<=k;++i)
    {
        fin>>x;
        A.push_back(x);
    }
    for(int i=1;i<=m;++i)
    {
        fin>>x>>y>>cost;
        G[x].push_back( std::make_pair(y,cost) );
        G[y].push_back( std::make_pair(x,cost) );
    }
    if(k==0)
    {
        dijkstra(1);
        fout<<d[n];
    }
    else
    {
        A.push_back(1);
        A.push_back(n);
        sort(A.begin(),A.end());
        for(int i=0;i<A.size();++i)
        {
            dijkstra(A[i]);
            for(int j=0;j<A.size();++j)
            {
                GP[A[i]].push_back( std::make_pair(A[j],d[A[j]]) );
                GP[A[j]].push_back( std::make_pair(A[i],d[A[j]]) );
            }
        }
        contor = 0;
        cost = 0;
        DFS(1);
        fout<<Maxim;
    }
    return 0;
}