#include <bits/stdc++.h>
#define int long long
// #define endl '\n'
using namespace std;

const int INF = 1e18;
struct Edge {
    int u, d;
};
vector<vector<Edge>> gr(10001, vector<Edge>());


vector<int> dijkstra(int start) {
    vector<int> dist(gr.size(), INF);
    dist[start] = 0;
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
    q.push({0, start});
    while (!q.empty()) {
        int v = q.top().second, d = q.top().first;
        q.pop();
        if (dist[v] < d) continue;
        for (auto [u, d] : gr[v]) {
            if (dist[v] + d < dist[u]) {
                dist[u] = dist[v] + d;
                q.push({dist[u], u});
            }
        }
    }
    return dist;
}

int dist[30][1 << 12];
struct Road {
    int v, u, d;
};

int solve() {
    int n, m; cin >> n >> m;
    int r; cin >> r;
    vector<int> vr;
    for (int i = 0; i < r; i++) {
        int c;
        cin >> c;
        c--;
        vr.push_back(c);
    }
    sort(vr.begin(), vr.end());
    vector<Road> main_r;
    for (int i = 0; i < m; i++) {
        int v, u, d; cin >> v >> u >> d;
        v--;
        u--;
        gr[v].push_back({u, d});
        gr[u].push_back({v, d});
        if (vr.size() && i == vr.front()) {
            main_r.push_back({v, u, d});
            vr.erase(vr.begin());
        }
    }
    set<int> s_main_c;
    for (int i = 0; i < r; i++) {
        s_main_c.insert(main_r[i].u);
        s_main_c.insert(main_r[i].v);
    }
    s_main_c.insert(0);
    s_main_c.insert(n - 1);
    vector<int> main_c(s_main_c.begin(), s_main_c.end());

    int k = main_c.size();
    int mat[k][k];
    for (int i = 0; i < k; i++) {
        vector<int> dist = dijkstra(main_c[i]);
        for (int j = 0; j < k; j++) {
            mat[i][j] = dist[main_c[j]];
        }
    }
    
    for (int i = 0; i < k; i++) {
        for (int j = 0; j < (1 << r); j++) {
            dist[i][j] = INF;
        }
        dist[i][0] = mat[0][i];
    }
    for (int s = 1; s < (1 << r); s++) {
        for (int i = 0; i < r; i++) {
            if (s & (1 << i)) {
                int v = main_r[i].v, u = main_r[i].u, d = main_r[i].d;
                dist[v][s] = min(dist[v][s], dist[u][s ^ (1 << i)] + d);
                dist[u][s] = min(dist[u][s], dist[v][s ^ (1 << i)] + d);
                for (int j = 0; j < k; j++) {
                    dist[j][s] = min(dist[j][s], dist[v][s] + mat[v][j]);
                    dist[j][s] = min(dist[j][s], dist[u][s] + mat[u][j]);
                }
            }
        }
    }
    cout << 1 << endl;
    // cout << dist[k - 1][(1 << r) - 1] << endl;

    return 1;
}

int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
    }
    return 0;
}