#include<cstdio>
#include<fstream>
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<vector>
#include<bitset>
#include<deque>
#include<queue>
#include<set>
#include<map>
#include<cmath>
#include<cstring>
#include<ctime>
#include<cstdlib>
#include<unordered_map>

#define ll long long
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define pll pair<ll,ll>
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second

using namespace std;

const int inf = 1 << 29;
const int pmax = 55;
const int nmax = 505;

int i, j, k, l, u, p, n, m, x, y, z, sol;
int d[nmax], dest[pmax];
int dp[pmax][pmax][pmax];
int dist[pmax][pmax];

vector<pii> v[nmax];
priority_queue<pii, vector<pii>, greater<pii>> q;
bitset<nmax> viz;

void dijkstra(int index)
{
    int source = dest[index];

    viz = 0;
    for(int i = 1; i <= n; i++)
        d[i] = inf;

    d[source] = 0;
    q.push(mp(0, source));

    while(!q.empty())
    {
        x = q.top().se;
        q.pop();

        if(viz[x]) continue;
        viz[x] = 1;

        for(auto it : v[x])
            if(d[x] + it.se < d[it.fi])
            {
                d[it.fi] = d[x] + it.second;
                q.push(mp(d[it.fi], it.fi));
            }
    }

    dist[index][0] = d[1];
    for(int i = 1; i <= p; i++)
        dist[index][i] = d[dest[i]];
}

int main()
{
    freopen("team.in", "r", stdin);
    freopen("team.out", "w", stdout);

    scanf("%d%d%d", &p, &n, &m);

    for(; m; m--)
    {
        scanf("%d%d%d", &x, &y, &z);
        v[x].pb(mp(y, z));
        v[y].pb(mp(x, z));
    }

    for(i = 1; i <= p; i++)
        scanf("%d", &dest[i]);

    for(i = 1; i <= p; i++)
        dijkstra(i);

    for(i = 1; i <= p; i++)
        for(j = 1; j <= p; j++)
            for(k = 1; k <= p; k++)
                dp[i][j][k] = inf;

    for(i = 1; i <= p; i++)
        for(j = 1; j <= p; j++)
            dp[i][i][j] = dist[i][j];

    for(l = 2; l <= p; l++)
        for(i = 1, j = i + l - 1; j <= p; i++, j++)
            for(k = 1; k <= p; k++)
                for(u = i; u <= j; u++)
                {
                    if(u == i) dp[i][j][k] = min(dp[i][j][k], dp[u + 1][j][u] + dist[u][k]);
                    else if(u == j) dp[i][j][k] = min(dp[i][j][k], dp[i][u - 1][u] + dist[u][k]);
                    else dp[i][j][k] = min(dp[i][j][k], dp[i][u - 1][u] + dp[u + 1][j][u] + dist[u][k]);
                }

    sol = inf;
    for(i = 1; i <= p; i++)
        sol = min(sol, dp[1][p][i] + dist[i][0]);

    printf("%d\n", sol);

    return 0;
}