#include <fstream>
#include <cstring>
#include <cassert>

using namespace std;

constexpr int MAX_N = 500;
constexpr int MAX_P = 50;
constexpr int INF = 0x3f3f3f3f;
constexpr int NIL = -1;

int edgeCost[MAX_N][MAX_N];

int residence[MAX_P + 1];
int dp[MAX_P][MAX_P][MAX_P + 1];

int pathWeight[MAX_P + 1][MAX_N];
bool color[MAX_N];

void Dijkstra(const int node,
              const int n,
              int weight[]) {
    memset(weight, 0x3f, 4 * n);
    memset(color, 0, n);
    weight[node] = 0;
    int best = node;
    for (int i = n - 1; i >= 0; i -= 1) {
        const int u = best;
        color[u] = true;
        int bestCost = INF;
        for (int son = 0; son < n; son += 1) {
            if (not(color[son])) {
                if (weight[son] > weight[u] + edgeCost[u][son]) {
                    weight[son] = weight[u] + edgeCost[u][son];
                }
                if (weight[son] < bestCost) {
                    bestCost = weight[son];
                    best = son;
                }
            }
        }
    }
}

int main() {
    ifstream fin("team.in");
    ofstream fout("team.out");
    fin.tie(0);
    ios_base::sync_with_stdio(false);
    int p, n, e; fin >> p >> n >> e;
    for (int i = 0; i < n; i += 1) {
        for (int j = 0; j < n; j += 1) {
            edgeCost[i][j] = INF;
        }
    }
    for (int i = 0; i < e; i += 1) {
        int node_1, node_2, weight; fin >> node_1 >> node_2 >> weight;
        edgeCost[node_1 - 1][node_2 - 1] = edgeCost[node_2 - 1][node_1 - 1] = weight;
    }
    for (int i = 0; i <= p; i += 1) {
        if (i) {
            fin >> residence[i]; residence[i] -= 1;
        }
        Dijkstra(residence[i],
                 n,
                 pathWeight[i]);
    }
    for (int i = 0; i < p; i += 1) {
        for (int k = 0; k <= p; k += 1) {
            dp[i][i][k] = pathWeight[i + 1][residence[k]];
        }
        for (int j = i + 1; j < p; j += 1) {
            for (int k = 0; k <= p; k += 1) {
                dp[i][j][k] = INF;
            }
        }
    }
    for (int st = p - 2; st >= 0; st -= 1) {
        for (int dr = st + 1; dr < p; dr += 1) {
            for (int node = 0; node <= p; node += 1) {
                int x = INF;
                for (int split = st; split <= dr; split += 1) {
                    const int option = dp[st][split - 1][split + 1]
                                    + pathWeight[node][residence[split + 1]]
                                    + dp[split + 1][dr][split + 1];
                    if (option < x) {
                        x = option;
                    }
                }
                dp[st][dr][node] = x;
            }
        }
    }
    fout << dp[0][p - 1][0] << '\n';
    fout.close();
    return 0;
}