#include <bits/stdc++.h>

using namespace std;

ifstream f("ubuntzei.in");
ofstream g("ubuntzei.out");

struct muc{
    int n,c;
};


const int nmax=2002;
const int kmax=17;
const int maskmax=(1<<kmax);
const int imax=0x3f3f3f3f;

int admat[kmax][kmax];
int ham[kmax][maskmax];


int prieten[nmax];
vector<muc> adj[nmax];
int n,m,k;

int dij[nmax];
void dodij(int st)
{
    for(int i=1;i<=n;i++) dij[i]=imax;
    dij[st]=0;

    priority_queue<pair<int,int>, vector<pair<int,int> >, greater<pair<int,int> > > q;

    q.push({0,st});

    while(!q.empty())
    {
        int cst=q.top().first,nod=q.top().second;
        q.pop();
        if(dij[nod]!=cst) continue;
        //cout<<"here "<<nod<<' '<<cst<<'\n';
        //cea mai importanta linie de cod
        if(prieten[nod]>0) admat[prieten[st]][prieten[nod]]=cst;
        for(auto e:adj[nod])
        {
            if(dij[e.n]>cst+e.c)
            {
                dij[e.n]=cst+e.c;
                q.push({dij[e.n],e.n});
            }
        }
    }

}


int main()
{
    f>>n>>m>>k;
    int a,b,c;

    for(int i=1;i<=k;i++)
    {
        f>>a;
        prieten[a]=i;
    }
    k++;
    prieten[n]=k;

    for(int i=1;i<=m;i++)
    {
        f>>a>>b>>c;
        adj[a].push_back({b,c});
        adj[b].push_back({a,c});
    }

    dodij(1);
    g<<admat[0][k]<<'\n';
    return 0;
}