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

using namespace std;

ifstream f ("team.in");
ofstream g ("team.out");

const int INF = (1 << 30);
const int NMAX = 500 + 1, PMAX = 50 + 1;

int p, n, m, l;
int destinatie[PMAX];
int d[PMAX][NMAX];
vector < pair <int, int> > graf[NMAX];
priority_queue < pair <int, int> > pq;

int dp[NMAX][NMAX][NMAX];
char s[100];

int get_number(int &i) {
    int x = 0;
    while (i < l && isdigit(s[i]))
        x = x * 10 + s[i] - '0',
        i++;
    return x;
}

void citeste() {
    f >> p >> n >> m;
    int a, b, c;
    f.getline(s, 99);
    int j;
    for (int i = 1; i <= m; i++) {
        f.getline(s, 99);
        l = strlen(s);
        j = 0;
        a = get_number(j);
        j++;
        b = get_number(j);
        j++;
        c = get_number(j);
        graf[a].push_back(make_pair(b, c));
        graf[b].push_back(make_pair(a, c));
    }

    for (int i = 1; i <= p; i++) f >> destinatie[i];
}


void dijkstra(int src, int d[]) {
    int fiu, l, nod, c, c2;
    pair <int, int> p;

    for (int i = 1; i <= n; i++) d[i] = INF;
    d[src] = 0;

    p.first = 0; p.second = src;
    pq.push(p);

    while(!pq.empty()) {
        p = pq.top();
        pq.pop();
        c = -p.first;
        nod = p.second;
        l = graf[nod].size();

        for (int i = 0; i < l; i++) {
            fiu = graf[nod][i].first;
            c2 = graf[nod][i].second + c;
            if (c2 < d[fiu]) {
                d[fiu] = c2;
                p.first = -c2;
                p.second = fiu;
                pq.push(p);
            }
        }
    }
}

void rezolva() {
    for (int i = 1; i <= p; i++) dijkstra(destinatie[i], d[i]);

    int j, min1, min2;
    min1 = min2 = INF;
    for (int lg = 2; lg <= p; lg++)
        for (int i = 1; i <= p; i++) {
            j = i + lg - 1;
            for (int k = i; k <= j; k++) {
                min1 = min2 = INF;
                for (int a = i; a < k; a++)      min1 = min(min1, dp[i][k - 1][a] + d[a][destinatie[k]]);
                for (int a = k + 1; a <= j; a++) min2 = min(min2, dp[k + 1][j][a] + d[a][destinatie[k]]);
                if (min1 == INF) min1 = 0;
                if (min2 == INF) min2 = 0;
                dp[i][j][k] = min1 + min2;
            }
        }

    int sol = INF;
    for (int i = 1; i <= p; i++)
        sol = min(sol, dp[1][p][i] + d[i][1]);
    g << sol;
}


int main() {
    citeste();
    rezolva();
    return 0;
}