#include<fstream>
#include<vector>
using namespace std;
ifstream f("ubuntzei.in");
ofstream g("ubuntzei.out");
struct da
{
    int x,y,c;
}v[10001];
int n,m,k;
int i,ok,x,y,c,inf;
int a[2001];
int d[2001];
int main()
{

    f>>n>>m;
    f>>k;
    for(i=1;i<=k;i++)
     f>>a[i];
    for(i=1;i<=m;i++)
    {
        f>>x>>y>>c;
        v[i].x=x;
        v[i].y=y;
        v[i].c=c;
        if(x==1)
         d[y]=c;
    }
    inf=1001;
    for(i=2;i<=n;++i)
     if(d[i]==0)
      d[i]=inf;
    do
    {
        ok=1;
        for(i=1;i<=m;++i)
         if(d[v[i].y]>d[v[i].x]+v[i].c)
         {
             d[v[i].y]=d[v[i].x]+v[i].c;
             ok=0;
         }
  }while (!ok);
  g<<d[n];
  return 0;
 }