#include <iostream>
#include <vector>
#include <queue>
#include <fstream>
#define dmax 100001
#define oo 1<<30
using namespace std;

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

int n,m,k,d[dmax],a[dmax];
bool InCoada[dmax];
vector< pair <int,int> >v[dmax];

struct compara
{
    bool operator()(int x,int y)
    {
        return d[x]>d[y];
    }
};

priority_queue<int , vector <int> , compara>q;

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

void dikjstra(int start)
{
    for(int i=1;i<=n;i++)
        d[i]=oo;
    d[start]=0;
    q.push(start);
    InCoada[start]=true;
    while(!q.empty())
    {
        int curent=q.top();
        q.pop();
        InCoada[curent]=false;
        for(int i=0;i<v[curent].size();i++)
        {
            int vecin=v[curent][i].first;
            int cost=v[curent][i].second;
            if(d[curent]+cost<d[vecin])
            {
                d[vecin]=d[curent]+cost;
                if(InCoada[vecin]==false)
                {
                    q.push(vecin);
                    InCoada[vecin]=true;
                }
            }
        }
    }
    for(int i=1;i<=n;i++)
        if(d[i]==oo)
        d[i]=0;
}

int main()
{
    citire();
    dikjstra(1);
    int suma=0;
    suma+=d[a[1]];
    for(int i=1;i<=k;i++)
    {
        dikjstra(a[i]);
        if(i==k)
            suma+=d[n];
        else suma+=d[a[i+1]];
    }
    fout<<suma;
    return 0;
}