#include <fstream>
#include <vector>
#include <queue>
#include <algorithm>
#include <climits>
using namespace std;
ifstream fin("ubuntzei.in");
ofstream fout("ubuntzei.out");
const int nmax=2005;
int n,m,k;
int loc[nmax],d[nmax][nmax];
bool inCoada[nmax];
const int inf=INT_MAX;
vector <pair<int,int>> muchii[nmax];
struct cmp
{
    bool operator() (int x,int y)
    {
        return d[x]>d[y];
    }
};
priority_queue <int,vector<int>,cmp> q;
void dijkstra(int start)
{
    while (!q.empty())
    {
        int nod=q.top();
        q.pop();
        inCoada[nod]=false;
        for (int i=0;i<muchii[nod].size();i++)
        {
            int vecin=muchii[nod][i].first;
            int cost=muchii[nod][i].second;
            if (d[start][nod]+cost<d[start][vecin])
            {
                d[start][vecin]=d[start][nod]+cost;
                if (inCoada[vecin]==false)
                {
                    q.push(vecin);
                    inCoada[vecin]=true;
                }
            }
        }
    }
}
int main()
{
    fin >> n >> m;
    fin >> k;
    for (int i=1;i<=k;i++)
    {
        fin >> loc[i];
    }
    for (int i=1;i<=m;i++)
    {
        int x,y,c;
        fin >> x >> y >> c;
        muchii[x].push_back(make_pair(y,c));
        muchii[y].push_back(make_pair(x,c));
    }
    for (int i=1;i<=n;i++)
    {
        for (int j=1;j<=n;j++)
        {
            d[i][j]=inf;
            inCoada[i]=false;
        }
        d[i][i]=0;
        inCoada[i]=true;
        q.push(i);
        dijkstra(i);
    }
    if (k==0) fout << d[1][n];
    else
    {
        sort(loc+1,loc+k+1);
        long long s=d[1][loc[1]];
        for (int i=2;i<k;i++)
        {
            s+=d[loc[i-1]][loc[i]];
        }
        s+=d[loc[k]][n];
        fout << s;
    }
}