#include <fstream>
#include<vector>
#include<queue>
#define pp pair<int,int>
using namespace std;
ifstream fin("ubuntzei.in");
ofstream fout("ubuntzei.out");
vector<pp> a[2001];
priority_queue<pp,vector<pp>,greater<pp> > q;
int n,m,d[10001];
void cit(){
    int k,i,j,h,w;
    fin>>n>>m;
    fin>>k;
    for(i=1;i<=k;i++)
        fin>>j;
    for(h=1;h<=m;h++){
        fin>>i>>j>>w;
        a[i].push_back(pp(j,w));
        a[j].push_back(pp(i,w));
    }
    fin.close();
}
void dijkstra(){
    pp p;
    int x,y,k,i;
    for(i=2;i<=n;i++)
        d[i]=9999999;
    q.push(pp(0,1));
    while(!q.empty()){
        p=q.top();
        q.pop();
        k=p.second;
        if(d[k]!=p.first)
            continue;
        for(i=0;i<a[k].size();i++){
            x=a[k][i].first;
            y=a[k][i].second;
            if(d[x]>d[k]+y){
                d[x]=d[k]+y;
                q.push(make_pair(d[x],x));
            }
        }
    }
}
int main(){
    cit();
    dijkstra();
    fout<<d[n];
    fout.close();
    return 0;
}