#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
vector<pair<int, int>> g[maxn];
map<int, int> d[maxn];
int spec[maxn];
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
int n, m, k; cin >> n >> m >> k;
for(int i = 1; i <= m; i++){
int u, v, w; cin >> u >> v >> w;
g[u].push_back({v, w});
g[v].push_back({u, w});
}
priority_queue<array<int, 3>, vector<array<int, 3>>, greater<array<int, 3>>> pq;
for(int i = 1; i <= k; i++){
int x; cin >> x;
pq.push({0, x, x});
spec[x] = 1;
d[x][x] = 0;
}
vector<array<int, 3>> banhhe;
int ans = 1e18;
while(pq.size()){
auto [dist, root, u] = pq.top();
pq.pop();
if(dist != d[root][u]) continue;
if(dist >= ans) break;
if(u != root && spec[u]){
for(int i = 0; i < banhhe.size(); i++){
auto [dist2, x, y] = banhhe[i];
if(x != root && x != u && y != root && y != u) ans = min(ans, dist2 + dist);
}
banhhe.push_back({dist, root, u});
}
for(auto [v, w]: g[u]){
if(d[root].find(v) != d[root].end() && d[root][v] <= dist + w) continue;
d[root][v] = dist + w;
pq.push({dist + w, root, v});
}
}
cout << ans;
return 0;
}
