#include <iostream>
#include <fstream>
#include <vector>
#include <set>
#define MAX 0x3f3f3f3f
using namespace std;

ifstream f("ubuntzei.in");
ofstream g("ubuntzei.out");

bool operator< (pair<int,int>a,pair<int,int>b)
{
    if (a.second==b.second)
        return a.first<b.first;
    return a.second<b.second;
}

vector<pair<int,int>>graph[2005];
set<pair<int,int>>q;
int n, m, nr_prieteni, y, from, to, cost, dp[2005];

void dijkstra()
{
    q.insert({1,0});
    while (!q.empty())
    {
        int nod=q.begin()->first;
        int cost=q.begin()->second;
        q.erase(q.begin());
        for (auto &v:graph[nod])
        {
            if (dp[nod]+v.second<dp[v.first])
            {
                if (dp[v.first]!=MAX)
                {
                    q.erase({v.first,dp[v.first]});
                }
                dp[v.first]=dp[nod]+v.second;
                q.insert({v.first,dp[v.first]});
            }
        }
    }
}

int main() {
    f >> n >> m;
    f >> nr_prieteni;
    for (int i=1; i<=nr_prieteni; i++)
        f >> y;
    for (int i=1; i<=m; i++)
    {
        f >> from >> to >> cost;
        graph[from].push_back(make_pair(to,cost));
        graph[to].push_back(make_pair(from,cost));
    }
    for (int i=2; i<=n; i++)
        dp[i]=0x3f3f3f3f;
    dijkstra();
    g << dp[n];
    return 0;
}