#include <fstream>
#include <vector>
#include <set>
using namespace std;
ifstream fin("ubuntzei.in");
ofstream fout("ubuntzei.out");
const int oo = 2e7;
int n, m, k, i, x, d, y, c;
vector <vector <pair <int, int>>> v;
set <pair <int, int>> q;
vector <int> dist, cit;
void dijkstra (int x0)
{
    for (i = 1; i <= n; i++)
        dist[i] = oo;
    dist[x0] = 0;
    q.insert(make_pair(0, x0));
    while (!q.empty())
    {
        x = (*q.begin()).second;
        q.erase(q.begin());
        for (i = 0; i < v[x].size(); i++)
        {
            y = v[x][i].first;
            c = v[x][i].second;
            if (dist[y] > dist[x] + c)
            {
                if (dist[y] != oo)
                    q.erase(q.find(make_pair(dist[y], y)));
                dist[y] = dist[x] + c;
                q.insert(make_pair(dist[y], y));
            }
        }
    }
}
int main()
{
    fin >> n >> m >> k; v.resize(n+1); dist.resize(n+1);
    for (i = 1; i <= k; i++)
    {
        fin >> x;
        cit.push_back(x);
    }
    for (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));
    }
    int xo = 1;
    while (!cit.empty())
    {
        dijkstra(xo);
        int mn = oo, p = 0;
        for (i = 0; i < k; i++)
        {
            if (mn > dist[i])
            {
                mn = dist[i];
                p = i;
            }
        }
        xo = cit[p];
        d += dist[xo];
        cit.erase(cit.begin()+p);
    }
    dijkstra(xo);
    d += dist[n];
    fout << d;
    return 0;
}