#include<fstream>
#include<cstdio>
#define INF 1000000000
using namespace std;
int n, m, k, nr, i, j, ii, jj, x, y, z, lg;
int a[505][505], a2[505][505], d[55][55][55], v[55], ff[505], dist[505][505], viz[505], d2[505], dest[55], h[505], poz[505];
FILE * fin = fopen("team.in", "r");
ofstream fout("team.out");
void upd(int c){
    int p = c / 2;
    while(p > 0 && d2[ h[p] ] > d2[ h[c] ]){
        swap(h[p], h[c]);
        poz[ h[p] ] = p;
        poz[ h[c] ] = c;
        c = p;
        p = c / 2;
    }
}
void elim(int p){
    int c = p + p;
    while(c <= n){
        if(c + 1 <= n && d2[ h[c] ] > d2[ h[c + 1] ]){
            c++;
        }
        if(d2[ h[p] ] > d2[ h[c] ]){
            swap(h[p], h[c]);
            poz[ h[p] ] = p;
            poz[ h[c] ] = c;
            p = c;
            c = p + p;
        }
        else{
            break;
        }
    }
}
void djikstra(int srs){
    int i, j, nod;
    for(i = 1; i <= n; i++){
        d2[i] = INF;
        viz[i] = 0;
        h[i] = poz[i] = i;
    }
    d2[srs] = 0;
    upd(srs);
    for(i = 1; i <= n; i++){
        nod = h[1];
        if(d2[nod] == INF){
            continue;
        }
        viz[nod] = 1;
        for(j = 1; j <= n; j++){
            if(a2[nod][j] == 1 && viz[j] == 0){
                d2[j] = min(d2[j], d2[nod] + a[nod][j]);
                upd(poz[j]);
            }
        }
        dist[srs][nod] = dist[nod][srs] = d2[nod];
        d2[nod] = INF;
        elim(poz[nod]);
    }
}
int solve(int i, int j, int ii){
    if(i > j){
        return 0;
    }
    if(d[i][j][ii] != INF){
        return d[i][j][ii];
    }
    for(int jj = i; jj <= j; jj++){
        d[i][j][ii] = min(d[i][j][ii], dist[ v[ii] ][ dest[jj] ] + solve(i, jj - 1, ff[ dest[jj] ]) + solve(jj + 1, j, ff[ dest[jj] ] ));
    }
    return d[i][j][ii];
}
int main(){
    fscanf(fin, "%d%d%d", &k, &n, &m);
    for(i = 1; i <= m; i++){
        fscanf(fin, "%d%d%d", &x, &y, &z);
        a[x][y] = a[y][x] = z;
        a2[x][y] = a2[y][x] = 1;
    }
    for(i = 1; i <= k; i++){
        fscanf(fin, "%d", &dest[i]);
        ff[ dest[i] ] = 1;
    }
    ff[1] = 1;
    for(i = 1; i <= n; i++){
        if(ff[i] == 1){
            v[++nr] = i;
            ff[i] = nr;
        }
    }
    for(i = 1; i <= nr; i++){
        djikstra(v[i]);
    }
    for(i = 1; i <= k; i++){
        for(j = 1; j <= k; j++){
            for(ii = 1; ii <= nr; ii++){
                d[i][j][ii] = INF;
            }
        }
    }
    for(i = 1; i <= k; i++){
        for(j = 1; j <= nr; j++){
            d[i][i][j] = dist[ dest[i] ][ v[j] ];
        }
    }
    fout<< solve(1, k, 1) <<"\n";
    return 0;
}