#include <cstdio>
#include <cstring>
#include <vector>
#include <queue>
#include <algorithm>

using namespace std;

#define sz(c) int((c).begin())
#define pb push_back

#define INF 0x3f3f3f3f
#define Nmax 512
#define Pmax 64
#define x first
#define y second

int n, p, m;
int c[Nmax][Nmax];
int dest[Pmax];

char viz[Pmax][Pmax][Nmax];
int A[Pmax][Pmax][Nmax];

vector< pair<int, int> > graph[Nmax];
char inQ[Nmax];

void readdata()
{
	freopen("team.in", "r", stdin);
	freopen("team.out", "w", stdout);

	scanf("%d %d %d", &p, &n, &m);
	for (int i = 1; i <= m; ++i)
	{
		int a, b, cost;
		scanf("%d %d %d", &a, &b, &cost);
		graph[a].push_back(make_pair(b, cost));
		graph[b].push_back(make_pair(a, cost));
	}
	for (int i = 1; i <= p; ++i)
		scanf("%d", &dest[i]);

}

int sol(int a, int b, int nod)
{
	if (a > b) return 0;
	if (viz[a][b][nod]) return A[a][b][nod];

	viz[a][b][nod] = 1;

	A[a][b][nod] = INF;
	for (int i = a; i <= b; ++i)
		A[a][b][nod] = min(A[a][b][nod], c[nod][dest[i]] + sol(a, i-1, dest[i]) + sol(i+1, b, dest[i]) );
	return A[a][b][nod];
}

void bellmanFord(int start) {
	memset(c[start], INF, sizeof(c[start]));
	c[start][start] = 0;

	memset(inQ, 0, sizeof(inQ));
	inQ[start] = 1;

	queue<int> q;
	q.push(start);
	while (!q.empty()) {
		int nod = q.front();
		q.pop();
		inQ[nod] = 0;

		for (vector< pair<int, int> >::iterator it = graph[nod].begin(); it != graph[nod].end(); ++it)
			if (c[start][it->x] > c[start][nod] + it->y) {
				c[start][it->x] = c[start][nod] + it->y;
				if (!inQ[it->x]) {
					q.push(it->x);
					inQ[it->x] = 1;
				}
			}
	}
}

int main()
{
	readdata();
	//for (int i = 1; i <= n; ++i)
	//	bellmanFord(i);
	printf("%d\n", sol(1, p, 1));
	return 0;
}