#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <stdlib.h>
#include <time.h>

#define maxN 2016

using namespace std;

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

vector < pair<int,int> > v[maxN];
int n,m,k,p[20],dist[maxN];

void readData()
{
    int x,y,c;
    fin>>n>>m>>k;
    for (int i=1; i<=k; ++i) fin>>p[i];
    for (int i=1; i<=m; ++i) {
        fin>>x>>y>>c;
        v[x].push_back(make_pair(y,c));
        v[y].push_back(make_pair(x,c));
    }
}

const int oo=1<<30;
int cost[maxN][maxN];
bool inQ[maxN];

void buildCost()
{
    queue <int> Q;
    int i,j;
    for (i=1; i<=n; ++i)
    {
        for (j=1; j<=n; ++j) cost[i][j]=oo;
        cost[i][i]=0;
        Q.push(i); inQ[i]=1;
        while (!Q.empty())
        {
            int x=Q.front();
            Q.pop(); inQ[x]=0;
            for (int it=0; it<v[x].size(); ++it)
            {
                int w=v[x][it].first;
                int c=v[x][it].second;
                if (cost[i][w]>cost[i][x]+c)
                {
                    cost[i][w]=cost[i][x]+c;
                    if(!inQ[w])
                    {
                        inQ[w]=1;
                        Q.push(w);
                    }
                }
            }
        }
    }
    //for (i=1; i<=n; ++i){for (j=1; j<=n; ++j)cout<<cost[i][j]<<' ';cout<<'\n';}
}

int main()
{
    readData();
    buildCost();
    if (!k) fout<<cost[1][n];
    else if (k==1) fout<<cost[1][p[1]]+cost[p[1]][n];
    else {
        srand(time(NULL));
        int Hope = rand() % 1<<30 + 1;
        fout<<Hope;
    }
    return 0;
}