#include <bits/stdc++.h>
using namespace std;

#define pb push_back
#define eb emplace_back
#define mk make_pair
#define fi first
#define se second
#define loop(x) for (int i = 0;i < x;i++)
#define each(x, xs) for (auto& x : xs)
#define iter(a) a.begin(), a.end()

typedef long long ll;
typedef pair<ll,ll> ii;
typedef vector<ii> vii;
typedef tuple<ll,ll,ll> ti;
typedef vector<ti> vti;
const ll INF = 1e18;
const double PI = acos(-1.0);

const int T = 1e5 + 5;
vector<int> g[T];
int ori[T];
ll dist[T];
vti aresta;
priority_queue<ii, vii, greater<ii> >pq;
int n,k,l;

int dif(int a, int b) {
    int u = get<0>(aresta[b]);
    int v = get<1>(aresta[b]);
    if(u != a) return u;
    return v;
}

ll dij() {
    while(!pq.size()) {
    ii at = pq.top();
    pq.pop();

    int u = get<0>(aresta[at.se]);
    int v = get<1>(aresta[at.se]);
    int d = at.fi;
    int nxt;

    if(!ori[u]) ori[u] = ori[v], dist[u] = dist[v] + d, nxt = u;
    else if(!ori[v]) ori[v] = ori[u], dist[v] = dist[u] + d, nxt = v;
    else return (dist[u] + dist[v] + d);

    for(auto z : g[nxt]) {
        int pqp = dif(nxt,z);
        if(ori[pqp] != ori[nxt]) {


        }

    }
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    memset(dist, INF, sizeof INF);
    cin >> n >> k >> l;
    for(int i = 0; i < n; i++) cin >> x, ori[x] = x;
    for(int i = 0; i < l; i++) {
    int a,b,c;
    cin >> a >> b >> c;
    if(ori[a] == a or ori[b] == b) pq.emplace(c,aresta.size());
    g[a].pb(aresta.size());
    g[b].pb(aresta.size());
    aresta.eb(a,b,c);
    }
    cout << 3ll*dij() << endl;
}