#pragma GCC optimize("O3,unroll-loops,inline")
#include <bits/stdc++.h>
#pragma GCC target("avx2")
using namespace std;
#define all(x) x.begin(), x.end()
using pint = pair<int, int>;
const int INF = 1e9;
int n, m, k;
vector<pint> adj[100001];
bool s[100001];
array<int, 3> mpair() {
vector<int> seen(n + 1), dist(n + 1, INF);
priority_queue<array<int, 3>> pq;
for (int i = 1; i <= n; ++i) {
if (s[i]) pq.push({0, i, i});
}
array<int, 3> mn{INF};
while (not pq.empty()) {
auto [d, i, p] = pq.top();
pq.pop();
if (not seen[i]) {
seen[i] = p;
dist[i] = -d;
} else {
if (seen[i] != p) mn = min(mn, array<int, 3>{-d + dist[i], seen[i], p});
continue;
}
if (-d >= mn[0]) continue;
for (auto &[j, x]: adj[i]) pq.push({d - x, j, seen[i]});
}
return mn;
}
vector<pint> sssp(int S) {
vector<int> dist(n + 1, INF);
priority_queue<pint> pq;
pq.emplace(0, S);
vector<pint> ret;
while (not pq.empty()) {
auto [d, i] = pq.top();
pq.pop();
if (-d >= dist[i]) continue;
if (s[i]) {
ret.emplace_back(i, -d);
if (ret.size() == 2) return ret;
}
dist[i] = -d;
for (auto &[j, x]: adj[i]) pq.emplace(d - x, j);
}
return {};
}
int main() {
cin.tie(nullptr);
ios_base::sync_with_stdio(false);
cin >> n >> m >> k;
while (m--) {
int u, v, w;
cin >> u >> v >> w;
adj[u].emplace_back(v, w);
adj[v].emplace_back(u, w);
}
while (k--) {
int i;
cin >> i;
s[i] = true;
}
auto [d, a, b] = mpair();
s[a] = s[b] = false;
int ans = d + mpair()[0];
auto dista = sssp(a), distb = sssp(b);
if (dista.size() == 2 and distb.size() == 2) {
if (dista[0].first != distb[0].first) ans = min(ans, dista[0].second + distb[0].second);
else ans = min({ans, dista[0].second + distb[1].second, dista[1].second + distb[0].second});
}
cout << ans;
}
