#include<bits/stdc++.h>
using namespace std;
#define int long long
#define all(a) (a).begin(), (a).end()
const int N=1e5+1;
int n, m, k, dd[N];
int dist[N], par[N], d1[N], d2[N];
vector<pair<int, int>> g[N];
pair<pair<int, int>, pair<int, int>> dijkstra(int root, int d[]){
memset(d, 0x3f, sizeof(int)*N);
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
d[root]=0;
pq.emplace(d[root], root);
pair<pair<int, int>, pair<int, int>> ans={{1e18, -1}, {1e18, -1}};
while (pq.size()){
int u=pq.top().second, f=pq.top().first;
pq.pop();
if (d[u]!=f) continue;
if (dd[u]){
if (ans.first.first>d[u]){
ans.second=ans.first;
ans.first={d[u], u};
}else ans.second=min(ans.second, {d[u], u});
}
for (auto &e:g[u]){
int v=e.first, w=e.second;
if (d[v]>d[u]+w){
d[v]=d[u]+w;
pq.emplace(d[v], v);
}
}
}
return ans;
}
pair<int, pair<int, int>> dijkstra(vector<int> root){
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
memset(dist, 0x3f, sizeof dist);
for (int x:root){
dist[x]=0; par[x]=x;
pq.emplace(dist[x], x);
}
pair<int, pair<int, int>> best={-1, {-1, -1}};
while (pq.size()){
int u=pq.top().second, d=pq.top().first; pq.pop();
if (dist[u]!=d) continue;
for (auto &e:g[u]){
int v=e.first, w=e.second;
if (par[u]!=par[v]){
if (best.first==-1) best={dist[u]+dist[v]+w, {par[u], par[v]}};
else best=min(best, {dist[u]+dist[v]+w, {par[u], par[v]}});
}
if (dist[v]>dist[u]+w){
dist[v]=dist[u]+w;
par[v]=par[u];
pq.emplace(dist[v], v);
}
}
}
return best;
}
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m >> k;
for (int i=1; i<=m; ++i){
int u, v, w; cin >> u >> v >> w;
g[u].emplace_back(v, w);
g[v].emplace_back(u, w);
}
vector<int> v(k);
for (int &i:v) cin >> i, dd[i]=1;
auto best1=dijkstra(v);
int t1=best1.second.first, t2=best1.second.second;
v.erase(find(all(v), t1));
v.erase(find(all(v), t2));
dd[t1]=dd[t2]=0;
auto g1=dijkstra(t1, d1);
auto g2=dijkstra(t2, d2);
auto best2=dijkstra(v);
int ans=best1.first+best2.first;
if (g1.first.second!=-1 && g2.first.second!=-1 && g1.first.second!=g2.first.second){
ans=min(ans, g1.first.first+g2.first.first);
}
if (g1.first.second!=-1 && g2.second.second!=-1 && g1.first.second!=g2.second.second){
ans=min(ans, g1.first.first+g2.second.first);
}
if (g1.second.second!=-1 && g2.first.second!=-1 && g1.second.second!=g2.first.second){
ans=min(ans, g1.second.first+g2.first.first);
}
cout << ans;
return 0;
}
