#include<stdio.h>
#include<stdlib.h>



typedef struct nod{
	int val;
	int cost;
	nod *next;
}nod;




int * dijkstra(nod **a,int n,int k)
{
	int *tata=(int *)malloc((n+1)*sizeof(int)),
		*distante=(int *)malloc((n+1)*sizeof(int)),
		*viz=(int *)malloc((n+1)*sizeof(int));

	for(int i=1;i<=n;i++)
	{
		distante[i]=INT_MAX;
		viz[i]=0;
		tata[i]=0;
	}
	nod*p=a[k];
	while (p)
	{
		distante[p->val]=p->cost;
		tata[p->val]=k;
		p=p->next;
	}
	viz[k]=1;
	int z;
	for(int i=1;i<n;i++)
	{
		int min=INT_MAX;
		for(int j=1;j<=n;j++)
		{
			if(distante[j]<min && viz[j]==0)
			{
				min=distante[j];
				z=j;
			}
		}
		viz[z]=1;
		for(p=a[z];p;p=p->next)
		{
			if(viz[p->val]==0 && distante[z]+p->cost<distante[p->val])
			{
				distante[p->val]=distante[z]+p->cost;
				tata[p->val]=z;
			}
		}
	}
	return distante;
}




int main()
{


	FILE*f=fopen("ubuntzei.in","r"),*fout=fopen("ubuntzei.out","w");
	int n,m,k,*v;
	fscanf(f,"%d",&n);
	fscanf(f,"%d",&m);
	fscanf(f,"%d",&k);
	v=(int *)malloc(k*sizeof(int));
	for(int i=0;i<k;i++)
		fscanf(f,"%d",&v[i]);
	nod **a=(nod**)malloc((n+1)*sizeof(nod*));
	for(int i=1;i<=n;i++)
		a[i]=NULL;
	int x,y,z;
	for(int i=1;i<=m;i++)
	{
		fscanf(f,"%d",&x);
		fscanf(f,"%d",&y);
		fscanf(f,"%d",&z);
		nod*p=(nod*)malloc(sizeof(nod)),*r=(nod*)malloc(sizeof(nod));
		p->val=y;
		p->next=r->next=NULL;
		p->cost=r->cost=z;
		r->val=x;
		if(a[x]==NULL)
		{
			a[x]=p;
		}
		else
		{
			nod *q=a[x];
			while (q->next)
			{
				q=q->next;
			}
			q->next=p;
		}
		if(a[y]==NULL)
		{
			a[y]=r;
		}
		else
		{
			nod *q=a[y];
			while (q->next)
			{
				q=q->next;
			}
			q->next=r;
		}
	}
	int **mat=(int **)malloc((n+1)*sizeof(int*));
	for(int i=1;i<=n;i++)
	{
		mat[i]=dijkstra(a,n,i);
	}
	int j,d=0,min,c;
	int b=1;
	for(int l=0;l<k;l++)
	{
		for(int i=0;i<k;i++)
		{
			min=INT_MAX;
			if(mat[b][v[i]]<min)
			{
				min=mat[b][v[i]];
				j=i;
			}
		}
		c=v[j];
		v[j]=0;
		b=j;
		d=min;
	}
	d+=mat[c][n];
	fprintf(fout,"%d",d);
	fclose(f);
	fclose(fout);
	return 0;
}