#include <bits/stdc++.h>

#define NMax 2005

using namespace std;

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

int N,M;
int K,C[NMax];
vector<pair<int,int> > Graf[NMax];
priority_queue<pair<int,int>,vector<pair<int,int> >,greater<pair<int,int> > > Queue;
int Dist[NMax];
bool mark[NMax];

void Read()
{
    fin>>N>>M>>K;
    for(int i=1;i<=K;i++)
        fin>>C[i];
    for(int i=1;i<=M;i++)
    {
        int x,y,c;
        fin>>x>>y>>c;
        Graf[x].push_back(make_pair(y,c));
        Graf[y].push_back(make_pair(x,c));
    }
}

void Dijkstra(int source)
{
    for(int i=1;i<=N;i++)
        mark[i]=false, Dist[i]=1<<30;
    Dist[source]=0;
    Queue.push(make_pair(source,Dist[source]));
    while(!Queue.empty())
    {
        int nod=Queue.top().first;
        int d=Queue.top().second;
        Queue.pop();
        if(Dist[nod]!=d)
            continue;
        for(vector<pair<int,int> >::iterator it=Graf[nod].begin();it!=Graf[nod].end();it++)
        {
            int to=it->first;
            int cost=it->second;
            if(Dist[to]>Dist[nod]+cost)
            {
                Dist[to]=Dist[nod]+cost;
                Queue.push(make_pair(to,Dist[to]));
            }
        }
    }
}

void SolveBrute()
{
    Dijkstra(1);
    fout<<Dist[N];
}

void SolveSmart()
{

}

int main()
{
    Read();
    if(K==0)
        SolveBrute();
    else
        SolveSmart();
    return 0;
}