#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 1, INF = 1e9;
int n;
vector<array<int, 2>> e[N];
bitset<N> is_special;
struct city_distance {
int city, source, dist;
bool operator<(const city_distance& rhs) const {
return dist > rhs.dist;
}
};
vector<city_distance> dijkstra(vector<int> sources, int threshold, int cnt) {
priority_queue<city_distance> pq;
vector<city_distance> v;
vector<set<int>> vis(n + 1);
for (int i : sources)
pq.push({i, i, 0});
while (!pq.empty()) {
city_distance cur = pq.top();
pq.pop();
if (vis[cur.city].count(cur.source))
continue;
vis[cur.city].insert(cur.source);
if (vis[cur.city].size() == cnt && is_special[cur.city]) {
v.push_back(cur);
if (v.size() == threshold)
return v;
}
for (auto i : e[cur.city])
if (!vis[i[0]].count(cur.source))
pq.push({i[0], cur.source, cur.dist + i[1]});
}
return v;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
int m, k, x, y, z, ans = INF;
cin >> n >> m >> k;
while (m--) {
cin >> x >> y >> z;
e[x].push_back({y, z});
e[y].push_back({x, z});
}
vector<int> special(k), new_special;
for (int i = 0; i < k; ++i) {
cin >> special[i];
is_special[special[i]] = 1;
}
city_distance close_pair = dijkstra(special, 1, 2)[0];
x = close_pair.city;
y = close_pair.source;
is_special[x] = 0;
is_special[y] = 0;
// Let a = x, and b = y, finding optimal c, d
for (int i : special)
if (i != x && i != y)
new_special.push_back(i);
vector<city_distance> other_close_pair = dijkstra(new_special, 1, 2);
if (!other_close_pair.empty())
ans = min(ans, close_pair.dist + other_close_pair[0].dist);
// Let a = x and c = y, finding optimal b, d
vector<city_distance> x_close, y_close;
x_close = dijkstra({x}, 2, 1);
y_close = dijkstra({y}, 2, 1);
for (int i = 0; i < x_close.size(); ++i)
for (int j = 0; j < y_close.size(); ++j)
if (x_close[i].city != y_close[j].city)
ans = min(ans, x_close[i].dist + y_close[j].dist);
cout << ans;
return 0;
}
