#include<fstream>
#include<vector>
#include<queue>
using namespace std;

int i,j,n,m,b[2010],x,y,c1,k;
unsigned long d[2010];
struct pc
{
	int nod,cost;
};
vector<pc> a[2010];
inline void det()
{
	int i,x;
	queue<int> q;
	q.push(1);
	for(i=1;i<=n;++i)
		d[i]=1<<30;
	d[1]=0;
	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()
{
	FILE *f=fopen("ubuntzei.in","r");
	FILE *g=fopen("ubuntzei.out","w");
	fscanf(f,"%d%d%d",&n,&m,&k);
	for(i=1;i<=k;++i)
		fscanf(f,"%d",&b[i]);
	for(i=1;i<=m;++i)
	{
		fscanf(f,"%d%d%d",&x,&y,&c1);
		a[x].push_back((pc) {y,c1});
		a[y].push_back((pc) {x,c1});
	}
	det();
	fprintf(g,"%ld",d[n]);
	return 0;
}