#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pi pair<int, int>
#define pii pair<int, pi>
#define fi first
#define se second
priority_queue<pi, vector<pi>, greater<pi> > pq;
int n,m,k;
vector<pi>v[100005];
int A[100005], dist[100005], stor[100005], stor2[100005], dist2[100005], dist3[100005], dist4[100005];
vector<pi>v2;
main(){
ios::sync_with_stdio(0); cin.tie(0);
cin >> n >> m >> k;
for(int i=1;i<=m;i++){
int x,y,z;
cin >> x >>y >> z;
v[x].push_back({y, z});
v[y].push_back({x, z});
}
for(int i=1;i<=n;i++)dist[i] = dist2[i] = dist3[i] = dist4[i] = 1e9;
for(int i=1;i<=k;i++){
cin >> A[i];
pq.push({0, A[i]}), dist[A[i]] = 0, stor[A[i]] = i;
}
while(!pq.empty()){
int x = pq.top().se, y = pq.top().fi;
pq.pop();
if(dist[x] < y)continue;
for(auto a : v[x]){
int i = a.fi, j = a.se;
if(dist[i] > j + y)dist[i] = j + y, pq.push({j+y, i}), stor[i] = stor[x];
}
}
int ans = 1e18;
int in, in2;
for(int i=1;i<=n;i++){
for(auto j : v[i]){
if(stor[i] != stor[j.fi]){
if(ans > dist[i] + dist[j.fi] + j.se)ans = dist[i] + dist[j.fi] + j.se, in = stor[i], in2 = stor[j.fi];
}
}
}
for(int i=1;i<=k;i++){
if(i == in || i == in2)continue;
pq.push({0, A[i]}), dist2[A[i]] = 0, stor2[A[i]] = i;
}
while(!pq.empty()){
int x = pq.top().se, y = pq.top().fi;
pq.pop();
if(dist2[x] < y)continue;
for(auto a : v[x]){
int i = a.fi, j = a.se;
if(dist2[i] > j + y)dist2[i] = j + y, pq.push({j+y, i}), stor2[i] = stor2[x];
}
}
int ans2 = 1e18;
for(int i=1;i<=n;i++){
for(auto j : v[i])if(stor2[i] != stor2[j.fi])ans2 = min(ans2, dist2[i] + dist2[j.fi] + j.se);
}
pq.push({0, A[in]});
while(!pq.empty()){
int x = pq.top().se, y = pq.top().fi;
pq.pop();
if(dist3[x] < y)continue;
for(auto a : v[x]){
int i = a.fi, j = a.se;
if(dist3[i] > j + y)dist3[i] = j + y, pq.push({j+y, i});
}
}
pq.push({0, A[in2]});
while(!pq.empty()){
int x = pq.top().se, y = pq.top().fi;
pq.pop();
if(dist4[x] < y)continue;
for(auto a : v[x]){
int i = a.fi, j = a.se;
if(dist4[i] > j + y)dist4[i] = j + y, pq.push({j+y, i});
}
}
int ans3 = 1e18;
int in3, mini = 1e18;
for(int i=1;i<=k;i++){
if(i == in || i == in2)continue;
v2.push_back({dist3[A[i]], A[i]});
}
sort(v2.begin(), v2.end());
for(int i=1;i<=k;i++){
if(i == in || i == in2)continue;
if(A[i] == v2[0].se){
ans3 = min(ans3, v2[1].fi + dist4[v2[0].se]);
}
else ans3 = min(ans3, v2[0].fi + dist4[A[i]]);
}
//cout << ans + ans2 << " " << ans3 << " " << in << " " << in2 << '\n';
cout << min(ans + ans2, ans3);
}
