#include <bits/stdc++.h>
using namespace std;
struct node {
  long long lvl1, lvl2, id;
};
node t[500005];
bool cmp(struct node x, struct node y) {
  if (x.lvl1 < y.lvl1)
    return true;
  else
    return false;
}
vector<node> sh;
vector<long long> adj[500005];
long long vis[500005], lvl1[500005], lvl2[500005];
void bfs1(long long n = 1) {
  queue<long long> q;
  q.push(n);
  vis[n] = 1;
  lvl1[n] = 0;
  while (!q.empty()) {
    long long x = q.front();
    q.pop();
    for (auto &cv : adj[x]) {
      if (vis[cv]) continue;
      q.push(cv);
      vis[cv] = 1;
      lvl1[cv] = lvl1[x] + 1;
    }
  }
}
void bfs2(long long n) {
  queue<long long> q;
  q.push(n);
  vis[n] = 1;
  lvl2[n] = 0;
  while (!q.empty()) {
    long long x = q.front();
    q.pop();
    for (auto &cv : adj[x]) {
      if (vis[cv]) continue;
      q.push(cv);
      vis[cv] = 1;
      lvl2[cv] = lvl2[x] + 1;
    }
  }
}
node combine(node x, node y) {
  if (x.lvl2 > y.lvl2)
    return x;
  else
    return y;
}
void build(long long n) {
  for (long long i = n - 1; i > 0; --i)
    t[i] = combine(t[i << 1], t[i << 1 | 1]);
}
node query(long long l, long long r, long long n) {
  node res;
  res.lvl2 = res.lvl1 = res.id = 0;
  for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
    if (l & 1) res = (combine(t[l++], res));
    if (r & 1) res = combine(t[--r], res);
  }
  return res;
}
long long arr[500005];
int32_t main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  long long i, j, k, l, m, n, x, y;
  cin >> n >> m >> k;
  for (i = 0; i < k; i++) {
    cin >> arr[i];
  }
  for (i = 0; i < m; i++) {
    cin >> x;
    cin >> y;
    adj[x].push_back(y);
    adj[y].push_back(x);
  }
  bfs1();
  memset(vis, 0, sizeof vis);
  bfs2(n);
  for (i = 0; i < k; i++) {
    node temp;
    temp.id = arr[i];
    temp.lvl1 = lvl1[arr[i]];
    temp.lvl2 = lvl2[arr[i]];
    sh.push_back(temp);
  }
  sort(sh.begin(), sh.end(), cmp);
  for (i = 0; i < sh.size(); i++) {
    t[i + k].lvl1 = sh[i].lvl1;
    t[i + k].lvl2 = sh[i].lvl2;
    t[i + k].id = sh[i].id;
  }
  build(k);
  long long ans = 0;
  for (i = 0; i + 1 < sh.size(); i++) {
    long long temp;
    temp = sh[i].lvl1;
    temp++;
    temp += query(i + 1, sh.size(), sh.size()).lvl2;
    ans = max(ans, temp);
  }
  cout << min(lvl2[1], ans) << endl;
  return 0;
}
