#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 5;
vector<pair<int, int> > adj[N];
int n, d[N], dx1[N], dy1[N], p[N];
set<int> S;
bool vis[N];
bool skip[N];
vector<pair<pair<int, int>, int> > E;
priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > Q;
void djikstra() {
while(!Q.empty()) {
int u = Q.top().second;
Q.pop();
if(vis[u]) continue;
vis[u] = 1;
for(auto nbr : adj[u]) {
int v = nbr.first, w = nbr.second;
if(skip[v]) continue;
if(d[u] + w < d[v]) {
d[v] = d[u] + w;
Q.push({d[v], v});
p[v] = p[u];
}
}
}
}
void run(int src) {
while(!Q.empty()) Q.pop();
for(int i = 1; i <= n + 4; i++) d[i] = INT_MAX, vis[i] = 0;
d[src] = 0;
p[src] = src;
Q.push({0, src});
djikstra();
}
pair<pair<int, int>, int> run_nearest() {
while(!Q.empty()) Q.pop();
for(int i = 1; i <= n + 4; i++) d[i] = INT_MAX, vis[i] = 0;
for(auto u : S) {
if(skip[u]) continue;
Q.push({0, u});
d[u] = 0;
p[u] = u;
}
djikstra();
int ans = INT_MAX, a = -1, b = -1;
for(auto e : E) {
int u = e.first.first, v = e.first.second, w = e.second;
if(skip[u] == 1 or skip[v] == 1) continue;
if(d[u] == INT_MAX or d[v] == INT_MAX or p[u] == p[v]) continue;
if(ans > d[u] + w + d[v]) {
ans = d[u] + w + d[v];
a = p[u], b = p[v];
}
}
return {{a, b}, ans};
}
int main() {
cin.tie(NULL);
ios::sync_with_stdio(false);
srand(time(NULL));
int m, k, u, v, w;
cin>>n>>m>>k;
while(m--) {
cin>>u>>v>>w;
adj[u].push_back({v, w});
adj[v].push_back({u, w});
E.push_back({{u, v}, w});
}
for(int i = 1; i <= k; i++) {
cin>>u;
S.insert(u);
}
pair<pair<int, int>, int> tmp = run_nearest();
int x1 = tmp.first.first, y1 = tmp.first.second, d1 = tmp.second;
int c1 = -1, c2 = -1;
run(x1);
for(int i = 1; i <= n; i++) dx1[i] = d[i];
run(y1);
for(int i = 1; i <= n; i++) dy1[i] = d[i];
for(auto c : S) {
if(c == x1 or c == y1) continue;
if(c1 == -1 or dy1[c] <= dy1[c1]) {
c2 = c1;
c1 = c;
} else if(c2 == -1 or dy1[c] < dy1[c2]) {
c2 = c;
}
}
int ans = INT_MAX, a1 = -1, a2 = -1, a3 = -1, a4 = -1;
if(dx1[c1] != INT_MAX and dy1[c2] != INT_MAX) {
if(ans > dx1[c1] + dy1[c2]) {
ans = dx1[c1] + dy1[c2];
a1 = x1, a2 = c1, a3 = y1, a4 = c2;
}
}
for(auto x2 : S) {
if(x2 == x1 or x2 == y1 or x2 == c1) continue;
if(dx1[x2] != INT_MAX and dy1[c1] != INT_MAX) {
if(ans > dx1[x2] + dy1[c1]) {
ans = dx1[x2] + dy1[c1];
a1 = x1, a2 = x2, a3 = y1, a4 = c1;
}
}
}
//Try commenting this portion and then checking if it fails or not.
skip[x1] = skip[y1] = 1;
tmp = run_nearest();
int d2 = tmp.second;
if(d1 != INT_MAX and d2 != INT_MAX) {
if(ans > d1 + d2) {
ans = d1 + d2;
a1 = x1, a2 = y1, a3 = tmp.first.first, a4 = tmp.first.second;
}
}
cout<<ans<<endl;
//cerr<<a1<<" "<<a2<<" "<<a3<<" "<<a4<<endl;
}
