#include <iostream>
#include <cstdio>
#include <queue>
#include <vector>
#include <bitset>
#define pii pair<int, int>
#define ppi pair<pii, int>
#define ppp pair<pii, pii>
#define fst first
#define snd second
#define vi vector<int>
#define vpi vector<pii>
#define pub push_back
using namespace std;
vector<vpi> adj;
priority_queue<ppi, vector<ppi>, greater<ppi>> pq;
bitset<100001> special;
const int MX = 1000000000;
int n, m, k, visited[100001][2] = {};
//inline int getchar_unlocked() {return getchar();}
inline bool isNum(char c) {return '0' <= c && c <= '9';}
inline int fast_input()
{
int c = 0, rs = 0;
while (!isNum(c)) {c = getchar_unlocked();}
while (isNum(c))
{
rs = 10 * rs + (c - '0');
c = getchar_unlocked();
}
return rs;
}
inline ppp dijkstra(int s)
{
int u, c;
for (int i = 0; i < n; i++) {visited[i][0] = MX;}
ppp tp = {{-1, -1}, {-1, -1}};
pq.push({{0, s}, 0});
while (!pq.empty())
{
u = pq.top().fst.snd, c = pq.top().fst.fst; pq.pop();
if (c <= visited[u][0])
{
visited[u][0] = c;
if (special[u])
{
if (tp.fst.fst == -1) {tp.fst = {u, c};}
else if (tp.snd.fst == -1)
{
tp.snd = {u, c};
while (pq.size()) {pq.pop();}
return tp;
}
}
for (auto v : adj[u])
{
if (c + v.snd < visited[v.fst][0])
{
visited[v.fst][0] = c + v.snd;
pq.push({{c + v.snd, v.fst}, 0});
}
}
}
}
return tp;
}
inline ppi findShortestPair()
{
int u, c, p;
for (int i = 0; i < n; i++) {visited[i][0] = MX; visited[i][1] = -1;}
ppi rs = {{-1, -1}, MX};
while (!pq.empty())
{
u = pq.top().fst.snd, c = pq.top().fst.fst, p = pq.top().snd; pq.pop();
if (c <= visited[u][0])
{
visited[u][0] = c;
visited[u][1] = p;
for (auto v : adj[u])
{
if (c + v.snd < visited[v.fst][0])
{
if (visited[v.fst][0] + c + v.snd < rs.snd && visited[v.fst][1] != -1 && visited[v.fst][1] != p)
{
rs.fst.fst = visited[v.fst][1];
rs.fst.snd = p;
rs.snd = visited[v.fst][0] + c + v.snd;
}
visited[v.fst][0] = c + v.snd;
visited[v.fst][1] = p;
pq.push({{c + v.snd, v.fst}, p});
}
else if (visited[v.fst][0] + c + v.snd < rs.snd && visited[v.fst][1] != p)
{
rs.fst.fst = visited[v.fst][1];
rs.fst.snd = p;
rs.snd = visited[v.fst][0] + c + v.snd;
}
}
}
}
return rs;
}
int main()
{
n = fast_input();
m = fast_input();
k = fast_input();
for (int i = 0; i < n; i++) {adj.pub(vpi());}
for (int i = 0; i < m; i++)
{
int u, v, w;
u = fast_input();
v = fast_input();
w = fast_input();
adj[u - 1].pub({v - 1, w});
adj[v - 1].pub({u - 1, w});
}
for (int i = 0; i < k; i++)
{
int x;
x = fast_input();
special[x - 1] = 1;
//mp[find(x - 1)].pub(x);
pq.push({{0, x - 1}, x - 1});
}
int rs = 1e9;
ppi rs1 = findShortestPair();
special[rs1.fst.snd] = 0;
special[rs1.fst.fst] = 0;
//cout << rs1.fst.snd << " " << rs1.fst.fst << " " << rs1.snd << "\n";
ppp o = dijkstra(rs1.fst.fst), s = dijkstra(rs1.fst.snd);
//cout << o.fst.fst << " " << o.fst.snd << " " << o.snd.fst << " " << o.snd.snd << "\n";
//cout << s.fst.fst << " " << s.fst.snd << " " << s.snd.fst << " " << s.snd.snd << "\n";
if (o.fst.fst + 1 && s.fst.fst + 1)
{
if (o.fst.fst == s.fst.fst)
{
if (o.snd.fst + 1) rs = min(rs, o.snd.snd + s.fst.snd);
if (s.snd.fst + 1) rs = min(rs, o.fst.snd + s.snd.snd);
}
else {rs = o.fst.snd + s.fst.snd;}
}
for (int i = 0; i < n; i++)
{
if (special[i]) {pq.push({{0, i}, i});}
}
//cout << findShortestPair().fst.fst << " " <<findShortestPair().fst.snd << " " << findShortestPair().snd << "\n";
rs = min(rs, rs1.snd + findShortestPair().snd);
printf("%d\n", rs);
return 0;
}
