#include <bits/stdc++.h>
using namespace std;
#define int long long
#define nl '\n'
const int INF = 1e15;
const int MOD = 1e9+7;
const int MXN = 1e5+9;
vector<array<int,2>> g[MXN];
int n, m, k;
int magic(vector<int> &s, vector<int> &f) {
priority_queue<array<int,2>, vector<array<int,2>>, greater<array<int,2>>> pq;
vector<bool> inf(n, 0);
for (int i : s) pq.push({0, i});
for (int i : f) inf[i] = 1;
vector<bool> vis(n, 0);
while (!pq.empty()) {
auto u = pq.top();
pq.pop();
if (vis[u[1]]) continue;
vis[u[1]] = 1;
if (inf[u[1]]) return u[0];
for (auto v : g[u[1]]) if (!vis[v[1]]) {
pq.push({u[0] + v[0], v[1]});
}
}
return INF;
}
int32_t main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
cin>>n>>m>>k;
for (int i = 0; i < m; i++) {
int a, b, wt; cin>>a>>b>>wt;
--a, --b;
g[a].push_back({wt,b});
g[b].push_back({wt,a});
}
vector<int> special(k);
for (int &i : special) cin>>i, --i;
int ans = INF;
while (clock() < 5.5*CLOCKS_PER_SEC) {
shuffle(special.begin(), special.end(), rng);
vector<int> start1, finish1, start2, finish2;
for (int i = 0; i < k; i++) {
if (i < k/4) start1.push_back(special[i]);
else if (i < k/2) finish1.push_back(special[i]);
else if (i < 3*k/4) start2.push_back(special[i]);
else finish2.push_back(special[i]);
}
int d = 0;
d += magic(start1, finish1);
d += magic(start2, finish2);
ans = min(d, ans);
}
cout<<ans;
}
