#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
using namespace std;
#define int long long
#define pii pair<int,int>
#define ff first
#define ss second
#define sp << " " <<
#define all(cont) cont.begin(),cont.end()
#define vi vector<int>
const int inf = 2e18,N = 1e6+1,MOD = 1e9+7;
void solve() {
int n,k,m;
cin >> n >> k >> m;
int lim = (1<<k);
int dp[n+1][lim];
for (int i = 0;i<=n;i++) for (int j = 0;j<lim;j++) dp[i][j] = inf;
for (int i = 0;i<=n;i++) dp[i][0] = 0;
for (int i = 0;i<k;i++) {
int x;
cin >> x;
dp[x][(1<<i)] = 0;
}
priority_queue<pii,vector<pii>,greater<pii>> pq;
vector<pii> edges[n+1];
for (int i=1;i<=m;i++) {
int a,b,c;
cin >> a >> b >> c;
edges[a].push_back({b,c});
edges[b].push_back({a,c});
}
for (int i = 0;i<lim;i++) {
for (int j = 1;j<=n;j++) {
for (int s = i;s > 0;s = (s-1)&i) {
dp[j][i] = min(dp[j][i],dp[j][s]+dp[j][i^s]);
}
if (dp[j][i] != inf) pq.push({dp[j][i],j});
}
while (!pq.empty()) {
auto[c,city] = pq.top();
pq.pop();
if (c != dp[city][i]) continue;
for (auto it : edges[city]) {
if (dp[it.ff][i] > c+it.ss) {
dp[it.ff][i] = c+it.ss;
pq.push({c+it.ss,it.ff});
}
}
}
}
int ans = inf;
for (int i=1;i<=n;i++) ans = min(ans,dp[i][lim-1]);
if (ans >= inf) cout << -1 << '\n';
else cout << ans << '\n';
}
int32_t main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#ifdef Dodi
freopen("in.txt","r",stdin);
freopen("out.txt","w",stdout);
#endif
int t = 1;
//cin >> t;
while (t --> 0) solve();
}
