/** - dwuy -
／＞ フ
| _ _|
／`ミ _x ノ
/ |
/ ヽ ?
／￣| | | |
| (￣ヽ＿_ヽ_)_)
＼二つ
**/
#include <bits/stdc++.h>
#define fastIO ios_base::sync_with_stdio(false); cin.tie(NULL)
#define file(a) freopen(a".inp","r",stdin); freopen(a".out", "w",stdout)
#define fi first
#define se second
#define endl "\n"
#define len(s) (int)((s).size())
#define MASK(k)(1LL<<(k))
#define TASK "test"
#define int long long
using namespace std;
typedef tuple<int, int, int> tpiii;
typedef pair<double, double> pdd;
typedef pair<int, int> pii;
typedef long long ll;
const long long OO = 1e18;
const int MOD = 1e9 + 7;
const int INF = 1e9;
const int MX = 100005;
int n, m, k;
vector<pii> G[MX];
map<int, int> d[MX];
bitset<MX> khiep = 0;
int32_t main(){
fastIO;
//file(TASK);
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<tpiii, vector<tpiii>, greater<tpiii>> Q;
for(int i=1; i<=k; i++){
int x; cin >> x;
khiep[x] = 1;
d[x][x] = 0;
Q.push({0, x, x});
}
vector<pair<int, pii>> gg;
int ans = 1e18;
while(Q.size()){
int du, r, u;
tie(du, r, u) = Q.top();
Q.pop();
if(du != d[r][u]) continue;
if(u != r && khiep[u]){
// cerr << u << ' ' << r << endl;
for(int i=0; i<len(gg); i++){
int x, y; tie(x, y) = gg[i].se;
if(x != r && x != u && y != r && y != u){
// cout << gg[i].fi + du << endl;
ans = min(ans, gg[i].fi + du);
// return 0;
}
}
gg.push_back({du, {r, u}});
}
for(pii e: G[u]){
int v, c; tie(v, c) = e;
auto itr = d[r].find(v);
if(itr != d[r].end() && d[r][v] <= du + c) continue;
d[r][v] = du + c;
Q.push({du + c, r, v});
}
}
cerr << ans;
return 0;
}
