#include <fstream>
#include <cstring>
#include <vector>
#include <queue>

#define MAXN 2002
#define inf 0x3f3f3f3f

using namespace std;

ifstream fin("ubuntzei.in");
ofstream fout("ubuntzei.out");

int n, k, nr_p, aux, z, prieten[MAXN], m, sol[MAXN][25];

struct str{
    int node, pr, c;

    bool operator < (const str& other) const {
        if (c == other.c)
            return pr < other.pr;
        return c > other.c;
    }
};

struct two{
    int nod, cost;
};

vector <two> G[MAXN];
priority_queue <str> Q;

inline void Read() {
    int x, y;

    fin >> n >> m;

    fin >> k;

    for (int i = 1; i <= k; i++) {
        fin >> x;
        prieten[x] = 1;
    }

    for (int i = 1; i <= m; i++) {
        fin >> x >> y >> z;

        G[x].push_back({y, z});
        G[y].push_back({x, z});
    }
}

inline void Init() {
    memset(sol, inf, sizeof(sol));
}

inline int Dijkstra(int start) {
    sol[start][0] = 0;
    Q.push({start, 0, 0});

    while (!Q.empty()) {
        z = Q.top().node;
        aux = nr_p = Q.top().pr;

        for (auto x : G[z]) {
            if (prieten[x.nod] == 1)
                nr_p = aux + 1;
            else
                nr_p = aux;

            if (sol[x.nod][nr_p] > sol[z][aux] + x.cost) {
                sol[x.nod][nr_p] = sol[z][aux] + x.cost;

                Q.push({x.nod, nr_p, sol[x.nod][nr_p]});
            }
        }
        Q.pop();
    }

    return sol[n][k];
}

int main() {
    Read();
    Init();
    fout << Dijkstra(1);

    fin.close(); fout.close(); return 0;
}