#include <bits/stdc++.h>
#define ll long long
#define task "RELAYMARATHON"
using namespace std;
const int N = 1e5 + 16;
const ll INF = 1e18;
int n, m, K, u, v, a[N];
ll w, result;
vector < pair <int, ll> > adj[N];
/*
6 6 4
1 2 5
2 4 7
4 6 50
6 5 3
1 5 15
3 5 6
1 5 4 6
*/
/*
11 15 5
1 2 3
1 2 2
1 5 12
2 4 5
5 4 10
6 5 12
6 7 14
7 5 7
7 9 9
9 4 6
4 8 5
8 10 9
10 9 16
7 11 21
9 11 20
1 11 10 6 7
*/
namespace sub1 {
ll d[516][516];
priority_queue < pair <ll, int>, vector < pair <ll, int> >, greater < pair <ll, int> > > pq;
void dijkstra(int k, int t) {
for (int i = 1; i <= n; i++) {
d[t][i] = INF;
}
d[t][k] = 0;
pq.push({d[t][k], k});
while (!pq.empty()) {
pair <ll, int> top = pq.top();
pq.pop();
ll dist = top.first;
int u = top.second;
if (dist > d[t][u]) {
continue;
}
for (auto v : adj[u]) {
int vertex = v.first;
ll value = v.second;
if (d[t][vertex] > dist + value) {
d[t][vertex] = dist + value;
pq.push({d[t][vertex], vertex});
}
}
}
}
ll result = INF;
void solve() {
for (int i = 1; i <= K; i++) {
dijkstra(a[i], i);
}
for (int i = 1; i <= K; i++) {
for (int j = i + 1; j <= K; j++) {
for (int k = 1; k <= K; k++) {
for (int s = k + 1; s <= K; s++) {
if (a[i] != a[k] && a[i] != a[s] && a[j] != a[k] && a[j] != a[s]) {
result = min(result, d[i][a[j]] + d[k][a[s]]);
}
}
}
}
}
cout << result;
}
}
namespace sub2 {
ll d[516][516];
priority_queue < pair <ll, int>, vector < pair <ll, int> >, greater < pair <ll, int> > > pq;
void dijkstra(int k, int t) {
for (int i = 1; i <= n; i++) {
d[t][i] = INF;
}
d[t][k] = 0;
pq.push({d[t][k], k});
while (!pq.empty()) {
pair <ll, int> top = pq.top();
pq.pop();
ll dist = top.first;
int u = top.second;
if (dist > d[t][u]) {
continue;
}
for (auto v : adj[u]) {
int vertex = v.first;
ll value = v.second;
if (d[t][vertex] > dist + value) {
d[t][vertex] = dist + value;
pq.push({d[t][vertex], vertex});
}
}
}
}
ll result = INF;
void solve() {
for (int i = 1; i <= K; i++) {
dijkstra(a[i], i);
}
for (int i = 1; i <= K; i++) {
for (int j = 1; j <= K; j++) {
if (i == j) {
continue;
}
int e1 = -1, e2 = -1;
for (int k = 1; k <= K; k++) {
if (k == i || k == j) {
continue;
}
if (e1 == -1 || d[i][e1] > d[i][a[k]]) {
e1 = a[k];
}
}
for (int k = 1; k <= K; k++) {
if (k == i || k == j || a[k] == e1) {
continue;
}
if (e2 == -1 || d[j][e2] > d[j][a[k]]) {
e2 = a[k];
}
}
result = min(result, d[i][e1] + d[j][e2]);
}
}
cout << result;
}
}
int main() {
ios_base :: sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
cin >> n >> m >> K;
for (int i = 1; i <= m; i++) {
cin >> u >> v >> w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
}
for (int i = 1; i <= K; i++) {
cin >> a[i];
}
if (n <= 50) {
sub1 :: solve();
}
else {
sub2 :: solve();
}
return 0;
}
