#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 1000000000 //un miliard
#define Nmax 512
#define Pmax 64

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

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

void init()
{
	int i, j;
	
	for (i = 1; i <= n; ++i)
		for (j = 1; j <= n; ++j)
			c[i][j] = inf;
	for (i = 1; i <= n; ++i)
		c[i][i] = 0;
}

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

	int i, m, a, b, cost;

	scanf("%d %d %d", &p, &n, &m);
	init();
	for (i = 1; i <= m; ++i)
	{
		scanf("%d %d %d", &a, &b, &cost);
		c[a][b] = c[b][a] = cost;
	}
	for (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 roy_floyd()
{
	int i, j, k;

	for (k = 1; k <= n; ++k)
		for (i = 1; i <= n; ++i)
			for (j = 1; j <= n; ++j)
				c[i][j] = min(c[i][j], c[i][k] + c[k][j]);
}

int main()
{
	readdata();
	roy_floyd();
	printf("%d\n", sol(1, p, 1));
	return 0;
}