#include <cstdio>
#include <vector>
#include <utility>
#include <set>
using namespace std;
 
const int MAXN = 100100;
 
int ans, n, m, k, i, x, y, z, v, to, cs, qq;
bool a[MAXN];
vector<pair<int, int> > g[MAXN];
int d[MAXN];
set<pair<int, int> > s;
int l[MAXN];
 
inline int gt(int x) 
{
    if (l[x] < qq) d[x] = 1e9;
    l[x] = qq;
    return d[x];
}
inline void upd(int x, int y)
{
    l[x] = qq;
    d[x] = y;
}

int main() 
{
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    scanf("%d%d%d", &n, &m, &k);
    for (int i = 1; i <= k; i++) 
    {
        scanf("%d", &x);
        a[x] = 1;
    }
    for (int i = 1; i <= m; i++) 
    {
        scanf("%d%d%d", &x, &y, &z);
        g[x].push_back(make_pair(y, z));
        g[y].push_back(make_pair(x, z));
    }
    ans = 1e9;
    for (int i = 1; i <= n; i++)
    {
        if (!a[i]) continue;
        qq++;
        upd(i, 0);
        s.clear();
        s.insert(make_pair(0, i));
        int cn = 0;
        while (!s.empty())
        {
            if (s.begin()->first > ans) break;
            v = s.begin()->second, s.erase(s.begin());
            if (a[v])
            {
                cn++;
                if (cn > 1) 
                {
                    ans = min(ans, gt(v));
                    break;
                }
            } 
            for (int i = 0; i < g[v].size(); i++)
            {
                to = g[v][i].first;
                cs = g[v][i].second;
                if (gt(v) + cs < gt(to))
                {
                    s.erase(make_pair(gt(to), to));
                    upd(to, gt(v) + cs);
                    s.insert(make_pair(gt(to), to));
                }
            }
        }
    }
    printf("%d\n", ans);
    return 0;
}