#include <bits/stdc++.h>
using namespace std;
int n, m, k, u, v, a[200005], el, ans;
vector<int> adj[200005];
queue<int> q;
bool vis[200005];
int depth[200005], depthn[200005];
int main() {
  ios_base::sync_with_stdio(NULL);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> m >> k;
  for (int i = 1; i <= k; i++) {
    cin >> a[i];
  }
  for (int i = 1; i <= m; i++) {
    cin >> u >> v;
    adj[u].push_back(v);
    adj[v].push_back(u);
  }
  for (int i = 1; i <= n; i++) {
    vis[i] = 0;
  }
  q.push(1);
  vis[1] = 1;
  depth[1] = 0;
  int node;
  while (!q.empty()) {
    node = q.front();
    q.pop();
    for (int x : adj[node]) {
      if (vis[x]) continue;
      vis[x] = 1;
      depth[x] = depth[node] + 1;
      q.push(x);
    }
  }
  for (int i = 1; i <= n; i++) {
    vis[i] = 0;
  }
  q.push(n);
  vis[n] = 1;
  depthn[n] = 0;
  while (!q.empty()) {
    node = q.front();
    q.pop();
    for (int x : adj[node]) {
      if (vis[x]) continue;
      vis[x] = 1;
      depthn[x] = depthn[node] + 1;
      q.push(x);
    }
  }
  vector<pair<int, int> > v;
  int cek = 0, ee = 0, cekn = 0, een = 0;
  for (int i = 1; i <= k; i++) {
    if (depth[a[i]] >= depth[n]) {
      cek++;
      ee = a[i];
    }
    if (depthn[a[i]] >= depthn[1]) {
      cekn++;
      een = a[i];
    }
    if (cek == 2 || cekn == 2) {
      cout << depth[n] << endl;
      return 0;
    }
    if (ee != a[i] && een != a[i]) v.push_back(make_pair(depth[a[i]], a[i]));
  }
  sort(v.begin(), v.end());
  int minn = 1e9;
  for (int i = 1; i < v.size(); i++) {
    minn = min(minn, v[i].first - v[i - 1].first);
  }
  if (minn < 1e9) ans = depth[n] - max(0, minn - 1);
  if (cek == 0 && cekn == 0) {
    cout << ans << endl;
    return 0;
  }
  if (cek == 1 && cekn == 0) {
    cout << max(ans, min(depth[n], v[k - 2].first + 1 + depthn[ee])) << endl;
  } else if (cek == 0 && cekn == 1) {
    cout << max(ans, min(depth[n], depthn[v[0].second] + 1 + depth[een]))
         << endl;
  } else {
    ans = max(ans, min(depth[een] + 1 + depthn[ee], depth[n]));
    if (v.size() > 0) {
      ans = max(ans, min(depth[n], v[k - 3].first + 1 + depthn[ee]));
      ans = max(ans, min(depth[n], depthn[v[0].second] + 1 + depth[een]));
    }
    cout << ans << endl;
  }
}
