#include<fstream>
#include<vector>
#include<queue>
using namespace std;
int n,m,k,i,j,x,y,c;
unsigned long d[2001];
struct dijk
{
	int nod, cost;
};
vector<dijk> a[2001];
queue<int> q;

void bf(int x)
{
	int i;
	d[x]=0;
	q.push(x);
	while(!q.empty())
	{
		x=q.front();
		
		for(i=0;i<a[x].size();++i)
			if(d[a[x][i].nod]>d[x]+a[x][i].cost)
			{
				d[a[x][i].nod]=d[x]+a[x][i].cost;
				q.push(a[x][i].nod);
			}
			q.pop();
	}
}

int main()
{
	freopen("ubuntzei.in","r",stdin);
	freopen("ubuntzei.out","w",stdout);
	scanf("%d%d",&n,&m);
	scanf("%d",&k);
	for(i=1;i<=k;++i)
		scanf("%d",&j);
	for(i=1;i<=m;++i)
	{
		scanf("%d%d%d",&x,&y,&c);
		a[x].push_back((dijk){y,c});
		a[y].push_back((dijk){x,c});
	}
	for(i=1;i<=n;++i)
		d[i]=1<<30;
	
	bf(1);
	printf("%ld\n",d[n]);
	return 0;
}