/* -*- coding: utf-8 -*-
 *
 * 3263.cc:  No.3263 驕墓ｳ輔↑謨｣豁ｩ驕・- yukicoder
 */

#include<cstdio>
#include<vector>
#include<queue>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 100000;
const int C = 5;

/* typedef */

using vi = vector<int>;
using qi = queue<int>;

/* global variables */

vi nbrs[MAX_N];
int fs[MAX_N], ds[MAX_N * C];

/* subroutines */

/* main */

int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int i = 0; i < m; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    u--, v--;
    nbrs[u].push_back(v);
    nbrs[v].push_back(u);
  }
  
  int k;
  scanf("%d", &k);
  for (int i = 0; i < k; i++) {
    int ai;
    scanf("%d", &ai), ai--;
    fs[ai] = 1;
  }

  fill(ds, ds + n * C, -1);
  ds[0] = 0;
  qi q;
  q.push(0);
  int gd = -1;

  while (! q.empty()) {
    int u = q.front(); q.pop();
    int up = u / C, uc = u % C;

    if (up == n - 1) { gd = ds[u]; break; }

    for (auto vp: nbrs[up]) {
      int vc = fs[vp] ? uc + fs[vp] : 0;
      if (vc < C) {
	int v = vp * C + vc;
	if (ds[v] < 0) {
	  ds[v] = ds[u] + 1;
	  q.push(v);
	}
      }
    }
  }

  printf("%d\n", gd);
  
  return 0;
}