#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define f first
#define s second
#define pii pair<int32_t,int32_t>
#define ppii pair<int,pii>
#define vi vector<int>
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define F(n) for(int i=0;i<n;i++)
#define lb lower_bound
#define ub upper_bound
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);
#pragma GCC optimize ("03,unroll-lopps")
#define sz(x) (int)((x).size())
#define int long long
using namespace std;
const int mod=1e9+7,mxn=2e5,inf=1e9,minf=-1e9,lg=30,Mxn=1e9;
//#undef int
int n,k,m,d,q;
void setIO(string name){
ios_base::sync_with_stdio(0); cin.tie(0);
freopen((name+".in").c_str(),"r",stdin);
freopen((name+".out").c_str(),"w",stdout);
}
vector<pii>dist[mxn+10];
vector<pii>adj[mxn+10];
int have(int x,pii a){
for(auto i:dist[x])if(i==a)return 1;
return 0;
}
bool put(int x,pii a){
for(auto &i:dist[x])if(i.s==a.s){
if(i.f>a.f)return i.f=a.f,1;
return 0;
}
if(dist[x].size()<3)return dist[x].pb(a),1;
sort(all(dist[x]));
if(a.f<dist[x].back().f){
dist[x].pop_back();
dist[x].pb(a);
return 1;
}
return 0;
}
bool good(pii a,pii b){
if(a.f==b.f||a.f==b.s||a.s==b.f||a.s==b.s)return 0;
return 1;
}
int32_t main(){
fastio
cin>>n>>m>>k;
for(int i=0;i<m;i++){
int a,b,c;cin>>a>>b>>c;
adj[a].pb({b,c});
adj[b].pb({a,c});
}
vector<int>SP(k);
priority_queue<pair<int,pii>,vector<pair<int,pii>>,greater<pair<int,pii>>>pq;
for(auto &i:SP){
cin>>i;
pq.push({0,{i,i}});
}
while(!pq.empty()){
int C=pq.top().f,cur=pq.top().s.f,F=pq.top().s.s;
pq.pop();
if(cur!=F&&!have(cur,{C,F}))continue;
for(auto i:adj[cur]){
if(i.f!=F&&put(i.f,{C+i.s,F}))pq.push({C+i.s,{i.f,F}});
}
}
vector<pair<int,pii>>have;
for(auto i:SP){
for(auto j:dist[i])have.pb({j.f,{i,j.s}});
}
int ans=inf;
sort(all(have));
//brute check?
for(int i=0;i<have.size();i++)for(int j=i+1;j<have.size();j++){
if(good(have[i].s,have[j].s))ans=min(ans,have[i].f+have[j].f);
}
cout<<ans;
}
/*
*/
