// ~~ icebear love attttt ~~
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
template<class T>
bool minimize(T &a, const T &b) {
if (a > b) return a = b, true;
return false;
}
template<class T>
bool maximize(T &a, const T &b) {
if (a < b) return a = b, true;
return false;
}
#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebearat"
const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 1e5 + 5;
int n, m, k;
map<int, int> dist[N];
vector<ii> G[N];
struct state {
int root, node, dist;
bool operator < (const state &other) const {
return dist > other.dist;
}
};
priority_queue<state> Q;
vector<state> distances;
bool special[N];
void init(void) {
cin >> n >> m >> k;
FOR(i, 1, m) {
int u, v, w;
cin >> u >> v >> w;
G[u].pb(mp(v, w));
G[v].pb(mp(u, w));
}
FOR(i, 1, k) {
int x; cin >> x;
special[x] = true;
Q.push({x, x, 0});
dist[x][x] = 0;
}
}
void process(void) {
ll ans = INF;
while(!Q.empty()) {
auto x = Q.top(); Q.pop();
if (dist[x.root][x.node] != x.dist) continue;
if (x.dist > ans) break;
for(ii t : G[x.node]) {
int v, w; tie(v, w) = t;
if (x.dist + w > ans) continue;
if (dist[x.root].find(v) == dist[x.root].end() || dist[x.root][v] > x.dist + w) {
int &tmp = dist[x.root][v];
tmp = x.dist + w;
Q.push({x.root, v, tmp});
if (special[v]) {
for(auto p : distances)
if (p.root != x.root && p.root != v && p.node != x.root && p.node != v)
minimize(ans, (ll)p.dist + tmp);
distances.pb({x.root, v, tmp});
}
}
}
}
cout << ans;
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
int tc = 1;
// cin >> tc;
while(tc--) {
init();
process();
}
return 0;
}
