#include <bits/stdc++.h>
using namespace std;
const int INF=1e9+10;
int a[100001],d[100001],ch[100001],n,m,k,u,v,w,res=INF*2;
vector <pair <int, int>> ke[100001];
vector <int> ve[4];
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
int f(int s, int e){
priority_queue <pair <int, int>, vector <pair <int, int>>, greater <pair <int, int>>> q;
for (int i=1;i<=n;i++){
d[i]=INF;
ch[i]=0;
}
for (int i:ve[s]){
d[i]=0;
q.push({0,i});
}
for (int i:ve[e])
ch[i]=1;
while (!q.empty()){
auto [du,u]=q.top();
q.pop();
if (ch[u])
return du;
if (du!=d[u])
continue;
for (auto [v,w]:ke[u])
if (d[v]>d[u]+w){
d[v]=d[u]+w;
q.push({d[v],v});
}
}
return INF;
}
int main(){
ios_base::sync_with_stdio(NULL);cin.tie(nullptr);
cin >> n >> m >> k;
while (m--){
cin >> u >> v >> w;
ke[u].push_back({v,w});
ke[v].push_back({u,w});
}
for (int i=1;i<=k;i++)
cin >> a[i];
chrono::milliseconds ms(3000);
chrono::time_point<chrono::system_clock> end=chrono::system_clock::now()+ms;
while (chrono::system_clock::now()<end){
shuffle(a+1,a+k+1,rd);
for (int i=0;i<4;i++)
ve[i].clear();
for (int i=1;i<=k;i++)
ve[rd()%4].push_back(a[i]);
res=min(res,f(0,1)+f(2,3));
}
cout << res;
}
