6 2 3
1 3 5
1 4 7
2 8 12
3 8 4
4 9 12
9 10 2
1 2
8 9 10

9

# include<queue>
# include<stack>
# include<cstdio>
# include<cstring>
# include<algorithm>
# define MAXN 1000 + 10
# define MAXM 5000 + 10
# define INF 0x3f3f3f3f
using namespace std;

int t, s, d, cnt;
int vis[MAXN];
int head[MAXN];
int dist[MAXN];

struct node
{
	int from, to, val, next;
	
}p[MAXM];

void add(int u, int v, int w)
{
	p[cnt].from = u;
	p[cnt].to = v;
	p[cnt].val = w;
	p[cnt].next = head[u];
	head[u] = cnt++;
}

void get()
{
	int a, b, c;
	while(t--)
	{
		scanf("%d%d%d",&a,&b,&c);
		add(a, b, c);
		add(b, a, c);
	}
}

void init()
{
	cnt = 0;
	memset(head, -1, sizeof(head));
	memset(vis, 0, sizeof(head));
}

void spfa(int px)
{
	vis[px] = 1;
	dist[px] = 0;
	queue<int>Q;
	Q.push(px);
	
	while(!Q.empty())
	{
		int u = Q.front();
		Q.pop();
		vis[u] = 0;
		for(int i = head[u]; i != -1; i = p[i].next)
		{
			int v = p[i].to;
			if(dist[v] > dist[u] + p[i].val)
			{
				dist[v] = dist[u] + p[i].val;
				if(!vis[v])
				{
					vis[v] = 1;
					Q.push(v);
				}
			}
		}
	}
}
int main()
{
	while(scanf("%d%d%d",&t,&s,&d)!=EOF)
	{
		init();
		get();
		int r, x, time;
		while(s--)
		{
			scanf("%d",&x);
			add(0, x, 0);
			add(x, 0, 0);//比较纠结的地方在这里，将x点与源点的距离赋值为0
		}
		for(int i = 1; i <= 1000; i++)
		{
			dist[i] = INF;
		}
		spfa(0);
		time = INF;
		while(d--)
		{
			scanf("%d",&r);
			if(time > dist[r])
			 time = dist[r];
		}
		printf("%d\n",time);
	}
	return 0;
}