#include <bits/stdc++.h>
#define inf 0x3f3f3f3f
using namespace std;
ifstream in("ubuntzei.in");
ofstream out("ubuntzei.out");

int n,m,k,c[16],dp[16][2001];
bool viz[2001];
vector<pair<int,int>>graf[2001];
priority_queue<pair<int,int>>pq;

void read()
{
    in>>n>>m>>k;
    c[0]=1;
    for(int i=1;i<=k;i++) in>>c[i];
    for(int i=1;i<=m;i++)
    {
        int x,y,c;
        in>>x>>y>>c;
        graf[x].push_back({y,c});
        graf[y].push_back({x,c});
    }
}
void dijkstra(int start)
{
    memset(viz,0,sizeof(viz));
    for(int i=1;i<=n;i++) dp[start][i]=inf;
    dp[start][start]=0;
    pq.push({dp[start][start],start});
    while(!pq.empty())
    {
        int nod=pq.top().second,dist=-pq.top().first;
        pq.pop();
        if(viz[nod]) continue;
        viz[nod]=1;
        for(auto x:graf[nod])
        {
            int next=x.first,cost=x.second;
            if(cost+dist<dp[start][next])
            {
                dp[start][next]=cost+dist;
                pq.push({-dp[start][next],next});
            }
        }
    }
}
void solve()
{
    if(k==0)
    {
        dijkstra(1);
        out<<dp[1][n];
        return;
    }
    for(int i=0;i<=k;i++) dijkstra(c[i]);
    int rez=0;
    for(int i=1;i<=k;i++) rez+=dp[c[i-1]][c[i]];
    rez+=dp[c[k]][n];
    out<<rez;
}
int main()
{
    read();
    solve();
    return 0;
}