#include <bits/stdc++.h>
using namespace std;
#define int long long
typedef pair<int,int> pi;
#define f first
#define s second
#define FAST ios_base::sync_with_stdio(0); cin.tie(0);
const int maxn = 100010;
typedef pair<int,pi> pp;
#define p(x,y,z) pp(x,pi(y,z))
int dist[maxn],col[maxn];
int special[maxn];
int n,m,k;
vector <int> specials;
vector <pi> adjlist[maxn];
int A = -1, B = -1;
int test(int excludea, int excludeb) {
memset(dist,-1,sizeof dist);
memset(col,-1,sizeof col);
priority_queue <pi,vector<pi>,greater<pi>> pq;
for (auto cur: specials) {
if (cur == excludea or cur == excludeb) continue;
pq.push(pi(0,cur));
dist[cur] = 0;
col[cur] = cur;
}
while (!pq.empty()) {
pi cur = pq.top(); pq.pop();
int x = cur.s, d = cur.f;
//cout << "GO: " << x << " " << d << "\n";
if (dist[x] != d) continue;
for (auto i: adjlist[x]) {
if (dist[i.f] == -1 or dist[i.f] > d + i.s) {
dist[i.f] = d + i.s;
col[i.f] = col[x];
pq.push(pi(dist[i.f],i.f));
}
}
}
//cout << "NEW: " << excludea << " " << excludeb << "\n";
//for (int i =1;i<=n;i++) {
//cout << i << " " << dist[i] << " " << col[i] << "\n";
//}
pp ans = p(LLONG_MAX/2,0,0);
for (int i = 1; i <= n;i++) {
for (auto u: adjlist[i]) {
if (col[i] != col[u.f] and col[i] != -1 and col[u.f] != -1) {
if (dist[u.f] + dist[i] + u.s < ans.f) {
ans = p(dist[u.f] + dist[i] + u.s, col[u.f], col[i]);
}
}
}
}
//cout << "ANS: " << ans.f << " " << ans.s.f << " " << ans.s.s << "\n";
if (excludea == -1 or excludeb == -1) {
if (A == -1 and B == -1) {
A = ans.s.f; B = ans.s.s;
}
return ans.f + test(ans.s.f, ans.s.s);
} else return ans.f;
}
int32_t main() {
FAST
cin >> n >> m >> k;
for (int i =0;i<m;i++) {
int a,b,c; cin >> a >> b >> c;
adjlist[a].push_back(pi(b,c));
adjlist[b].push_back(pi(a,c));
}
for (int i =0;i<k;i++) {
int x; cin >> x;
special[x] = 1;
specials.push_back(x);
}
int rans = LLONG_MAX/2;
rans = min(rans,test(-1,-1));
rans = min(rans,test(A,-1));
rans = min(rans,test(B,-1));
cout << rans;
}
