#include <fstream>
#include <vector>
#include <bitset>
#include <queue>
#include <string.h>

using namespace std;

const char infile[] = "team.in";
const char outfile[] = "team.out";

ifstream fin(infile);
ofstream fout(outfile);

const int MAXN = 505;
const int MAXP = 55;
const int oo = 0x3f3f3f3f;

typedef vector< pair<int, int> > Graph[MAXN];
typedef vector< pair<int, int> > :: iterator It;

const inline int min(const int &a, const int &b) { if( a > b ) return b;   return a; }
const inline int max(const int &a, const int &b) { if( a < b ) return b;   return a; }
const inline void Get_min(int &a, const int b)    { if( a > b ) a = b; }
const inline void Get_max(int &a, const int b)    { if( a < b ) a = b; }

Graph G;
int P, N, M, dest[MAXP], d[MAXN][MAXN], dp[MAXP][MAXP][MAXN];
priority_queue < pair<int, int> , vector<pair<int, int> > , greater <pair<int, int> > > Q;

inline void Dijkstra(int st, int bst[]) {
    Q.push(make_pair(0, st));
    bst[st] = 0;
    for( ; !Q.empty() ; Q.pop()) {
        int Node = Q.top().second;
        for(It it = G[Node].begin(), fin = G[Node].end(); it != fin ; ++ it)
            if(bst[it->first] > bst[Node] + it->second) {
                bst[it->first] = bst[Node] + it->second;
                Q.push(make_pair(bst[it->first], it->first));
            }
    }
}

inline int Memo(const int &i, const int &j, const int &k) {
    if(i > j)
        return 0;
    if(dp[i][j][k] != oo)
        return dp[i][j][k];
    if(i == j)
        return d[i][j];
    for(int l = i ; l <= j ; ++ l)
        Get_min(dp[i][j][k], d[l][k] + Memo(i, i-1, dest[l]) + Memo(l + 1, j, dest[l]));
    return dp[i][j][k];
}

int main() {
    fin >> P >> N >> M;
    for(int i = 1 ; i <= M ; ++ i) {
        int x, y, z;
        fin >> x >> y >> z;
        G[x].push_back(make_pair(y, z));
        G[y].push_back(make_pair(x, z));
    }
    memset(d, oo, sizeof(d));
    memset(dp, oo, sizeof(dp));
    for(int i = 1 ; i <= P ; ++ i) {
        fin >> dest[i];
        Dijkstra(dest[i], d[i]);
    }
    fout << Memo(1, P, 1);
    fin.close();
    fout.close();
    return 0;
}