#include <bits/stdc++.h>
using namespace std;
std::mt19937 rng((int) std::chrono::steady_clock::now().time_since_epoch().count());
const int mxn = 100 * 1000 + 3;
const int inf = 1e9 + 2;
vector<array<int, 2>> g[mxn];
int n, m, k;
int magic(vector<int> &src, vector<int> &snk) {
priority_queue<array<int, 2>, vector<array<int, 2>>, greater<>> pq;
vector<int> dt(n, inf);
vector<bool> done(n);
for(int v : src) {
dt[v] = 0;
pq.push({0, v});
}
for(int &v : snk)
done[v] = true;
while(!pq.empty()) {
auto [wt, v] = pq.top();
pq.pop();
if(dt[v] != wt)
continue;
if(done[v])
return wt;
for(auto &[u, w] : g[v]) {
if(dt[v] + w < dt[u]) {
dt[u] = dt[v] + w;
pq.push({dt[u], u});
}
}
}
int ret = inf;
for(int &v : snk)
ret = min(ret, dt[v]);
return ret;
}
signed main() {
std::ios::sync_with_stdio(0);
std::cout.tie(0);
std::cin.tie(0);
#ifdef saarang
freopen("/home/saarang/Documents/cp/input.txt", "r", stdin);
freopen("/home/saarang/Documents/cp/output.txt", "w", stdout);
#endif
cin >> n >> m >> k;
for(int u, v, w, i = 0; i < m; i++) {
cin >> u >> v >> w;
g[--u].push_back({--v, w});
g[v].push_back({u, w});
}
vector<int> a(k);
for(int &x : a)
cin >> x, x--;
int ans = inf;
while(clock() < 5.5 * CLOCKS_PER_SEC) {
shuffle(a.begin(), a.end(), rng);
vector<int> src[2], snk[2];
for(int i = 0; i < k / 2; i++)
src[rng() % 2].push_back(a[i]);
for(int i = k / 2; i < k; i++)
snk[rng() % 2].push_back(a[i]);
ans = min(ans, magic(src[0], snk[0]) + magic(src[1], snk[1]));
}
cout << ans << '\n';
return 0;
}
