/* -*- coding: utf-8 -*-
 *
 * 1812.cc:  No.1812 Uribo Road - yukicoder
 */

#include<cstdio>
#include<vector>
#include<queue>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 10000;
const int MAX_M = 20000;
const int MAX_K = 12;
const int KBITS = 1 << MAX_K;
const int MAX_GN = MAX_K * 2 + 2;
const long long LINF = 1LL << 62;

/* typedef */

typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,int> pli;
typedef vector<pii> vpii;

/* global variables */

int rs[MAX_K], ers[MAX_M];
pii rvs[MAX_K];
vpii nbrs[MAX_N];
int cs[MAX_M], vs[MAX_GN], gbs[MAX_GN][MAX_GN];
ll ds[MAX_N], gcs[MAX_GN][MAX_GN], gds[MAX_GN * KBITS];

/* subroutines */

/* main */

int main() {
  int n, m, k;
  scanf("%d%d%d", &n, &m, &k);
  int kbits = 1 << k, kmsk = kbits - 1;

  fill(ers, ers + m, -1);
  for (int i = 0; i < k; i++) {
    scanf("%d", rs + i), rs[i]--;
    ers[rs[i]] = i;
  }

  int gn = 0;
  for (int i = 0; i < m; i++) {
    int u, v;
    scanf("%d%d%d", &u, &v, cs + i);
    u--, v--;
    nbrs[u].push_back(pii(v, i));
    nbrs[v].push_back(pii(u, i));
    if (ers[i] >= 0) {
      vs[gn++] = u, vs[gn++] = v;
      rvs[ers[i]] = pii(u, v);
    }
  }

  vs[gn++] = 0, vs[gn++] = n - 1;
  sort(vs, vs + gn);
  gn = unique(vs, vs + gn) - vs;

  for (int i = 0; i < gn; i++) {
    fill(ds, ds + n, LINF);
    ds[vs[i]] = 0;

    priority_queue<pli> q;
    q.push(pli(0, vs[i]));

    while (! q.empty()) {
      pli u = q.top(); q.pop();
      ll ud = -u.first;
      int ui = u.second;
      if (ds[ui] != ud) continue;

      for (auto ve: nbrs[ui]) {
	int vi = ve.first, ei = ve.second;
	ll vd = ud + cs[ei];

	if (ds[vi] > vd) {
	  ds[vi] = vd;
	  q.push(pli(-vd, vi));
	}
      }
    }

    for (int j = 0; j < gn; j++) gcs[i][j] = ds[vs[j]];
  }

  for (int i = 0; i < k; i++) {
    int u = rvs[i].first, v = rvs[i].second;
    int gu = lower_bound(vs, vs + gn, u) - vs;
    int gv = lower_bound(vs, vs + gn, v) - vs;
    gbs[gu][gv] = gbs[gv][gu] = 1 << i;
    if (gcs[gu][gv] < cs[rs[i]])
      gcs[gu][gv] = gcs[gv][gu] = cs[rs[i]];
  }

  int st = 0, gl = (gn - 1) << k | kmsk;

  fill(gds, gds + gn * kbits, LINF);
  gds[st] = 0;

  priority_queue<pli> gq;
  gq.push(pli(0, st));

  while (! gq.empty()) {
    pli u = gq.top(); gq.pop();
    ll ud = -u.first;
    int up = u.second;
    if (gds[up] != ud) continue;
    if (up == gl) break;

    int ui = up >> k, ub = up & kmsk;
    for (int vi = 0; vi < gn; vi++) {
      ll vd = ud + gcs[ui][vi];
      int vb = ub | gbs[ui][vi];
      int vp = vi << k | vb;
      if (gds[vp] > vd) {
	gds[vp] = vd;
	gq.push(pli(-vd, vp));
      }
    }
  }

  printf("%lld\n", gds[gl]);
  return 0;
}