#include <cstdio>
#include <vector>
#include <algorithm>
#include <queue>
using namespace std;

const int MAX_N = 512;
const int MAX_P = 64;
const int INF = 0x3f3f3f3f;

int n, m, p;
vector< pair<int, int> > graph[MAX_N];
int dest[MAX_P];
int indx[MAX_P];
int best[MAX_N];
int dmin[MAX_P][MAX_P];
int d[MAX_P][MAX_P][MAX_P];
char inQ[MAX_N];
queue<int> q;

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

	memset(inQ, 0, sizeof(inQ));
	inQ[start] = 1;
	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 (best[it->first] > best[nod] + it->second) {
				best[it->first] = best[nod] + it->second;
				if (!inQ[it->first]) {
					inQ[it->first] = 1;
					q.push(it->first);
				}
			}
	}
}

inline void checkMin(int &a, int b) { a = (a < b ? a : b); }

int sol(int a, int b, int cindx) {
	if (a > b) return 0;
	if (d[a][b][cindx] != INF) return d[a][b][cindx];

	for (int i = a; i <= b; ++i)
		checkMin(d[a][b][cindx], sol(a, i - 1, i) + sol(i + 1, b, i) + dmin[cindx][i]);
	return d[a][b][cindx];
}

int main() {
	freopen("team.in", "r", stdin);
	freopen("team.out", "w", stdout);

	// read
	scanf("%d %d %d\n", &p, &n, &m);
	for (int i = 0; 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]);

	// solve
	indx[1] = 0; dest[0] = 1;
	for (int i = 1; i <= p; ++i)
		indx[dest[i]] = i;
	
	for (int i = 0; i <= p; ++i) {
		bellmanFord(dest[i]);
		for (int j = 0; j <= p; ++j)
			dmin[i][j] = best[dest[j]];
	}

	memset(d, INF, sizeof(d));
	printf("%d\n", sol(1, p, 0));
	
}