#include <stdio.h>
#include <string.h>

#define MAXN 505
#define MAXP 55

int P, N, M;
int d[MAXN];
int dist[MAXN][MAXN];
int nr[MAXN][MAXP][MAXP];

int solve( int k, int l, int r )
{
	if (nr[k][l][r] != 0x3f3f3f3f)
		return nr[k][l][r];

	if (l == r)
		return dist[k][ d[l] ];

	int found = 0;
	for (int i = l; i <= r && !found; i++)
		if (d[i] == k)
			found = 1;

	if (found)
	{
		int rez = 0, last, i;
		for (i = l; d[i] == k && i <= r; i++);

		for (last = i; i <= r; )
			if (d[i] == k)
			{
				rez += solve(k, last, i - 1);
				for (; i <= r && d[i] == k; i++);
				last = i;
			}
			else
				i++;

		if (last <= r)
			rez += solve( k, last, r );
		return nr[k][l][r] = rez;
	}

	for (int i = l; i <= r; i++)
	{
		int rez = dist[k][ d[i] ] + solve( d[i], l, r );
		if (rez < nr[k][l][r])
			nr[k][l][r] = rez;
	}
	return nr[k][l][r];
}

int main()
{
	freopen("team.in", "rt", stdin);
	freopen("team.out", "wt", stdout);

	memset(dist, 0x3f, sizeof(dist));
	memset(nr, 0x3f, sizeof(nr));
	for (scanf("%d %d %d", &P, &N, &M); M; M--)
	{
		int i, j, k;
		scanf("%d %d %d", &i, &j, &k);
		dist[i][j] = dist[j][i] = k;
	}
	for (int i = 1; i <= P; i++)
		scanf("%d", d + i);

	for (int i = 1; i <= N; i++)
		dist[i][i] = 0;

	for (int k = 1; k <= N; k++)
		for (int i = 1; i <= N; i++)
			for (int j = 1; j <= N; j++)
				if (dist[i][k] + dist[k][j] < dist[i][j])
					dist[i][j] = dist[i][k] + dist[k][j];

	printf("%d\n", solve(1, 1, P));

	return 0;
}