#include <bits/stdc++.h>
#define INF 1000000001
#define L 2005
#define S 20
#define LL (1 << 18) + 5
#define INVALID -1
using namespace std;
ifstream fin("ubuntzei.in");
ofstream fout("ubuntzei.out");

int n, m, k;
vector <pair <int, int>> G[L];
vector <int> nodes;
int dist[L], cost[S][S], ham[LL][S];

void dijkstra(int src){
  priority_queue <pair <int, int>> pq;
  int i, node, cost;
  for (i = 1; i <= n; i++)
    dist[i] = INF;
  dist[src] = 0;
  pq.push({-dist[src], src});
  while (!pq.empty()){
    cost = -pq.top().first;
    node = pq.top().second;
    pq.pop();
    if (cost == dist[node])
      for (auto it : G[node])
        if (cost + it.second < dist[it.first]){
          dist[it.first] = cost + it.second;
          pq.push({-dist[it.first], it.first});
        }
  }
  for (i = 1; i <= n; i++)
    if (dist[i] == INF)
      dist[i] = 0;
}

int generate_ham(int n){
  for (int mask = 0; mask < (1 << n); mask++)
    for (int node = 0; node < n; node++)
      ham[mask][node] = INVALID;
  ham[1][0] = 0;
  for (int mask = 0; mask < (1 << n); mask++)
    for (int node = 1; node < n; node++){
      if (ham[mask | (1 << node)][node] != INVALID)
        continue;
      ham[mask | (1 << node)][node] = INF;
      for (int i = 0; i < n; i++)
        if (ham[mask][i] != INVALID && cost[i][node] != 0)
          ham[mask | (1 << node)][node] = min(ham[mask | (1 << node)][node], ham[mask][i] + cost[i][node]);
      if (ham[mask | (1 << node)][node] == INF)
        ham[mask | (1 << node)][node] = INVALID;
    }
  return ham[(1 << n) - 1][n - 1];
}

int main(){
  fin >> n >> m >> k;
  nodes.push_back(1);
  for (int i = 0; i < k; i++){
    int x;
    fin >> x;
    nodes.push_back(x);
  }
  nodes.push_back(n);
  for (int i = 0; i < m; i++){
    int a, b, c;
    fin >> a >> b >> c;
    G[a].push_back({b, c});
    G[b].push_back({a, c});
  }
  n = nodes.size();
  for (int i = 0; i < n; i++){
    dijkstra(nodes[i]);
    for (int j = 0; j < n; j++)
      cost[i][j] = dist[nodes[j]];
  }
  int ans = generate_ham(n);
  fout << ans << "\n";
  return 0;
}