#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
vector<string> vec_splitter(string s) {
  s += ',';
  vector<string> res;
  while (!s.empty()) {
    res.push_back(s.substr(0, s.find(',')));
    s = s.substr(s.find(',') + 1);
  }
  return res;
}
void debug_out(vector<string> __attribute__((unused)) args,
               __attribute__((unused)) int idx,
               __attribute__((unused)) int LINE_NUM) {
  cerr << endl;
}
template <typename Head, typename... Tail>
void debug_out(vector<string> args, int idx, int LINE_NUM, Head H, Tail... T) {
  if (idx > 0)
    cerr << ", ";
  else
    cerr << "Line(" << LINE_NUM << ") ";
  stringstream ss;
  ss << H;
  cerr << args[idx] << " = " << ss.str();
  debug_out(args, idx + 1, LINE_NUM, T...);
}
const long long MOD = (int)1e9 + 7;
const long long INF = 2e18 + 5;
struct hashLL {
  size_t operator()(long long x) const {
    x = (x ^ (x >> 30)) * UINT64_C(0xbf58476d1ce4e5b9);
    x = (x ^ (x >> 27)) * UINT64_C(0x94d049bb133111eb);
    x = x ^ (x >> 31);
    return x;
  }
};
long long inv(long long a, long long b) {
  return 1 < a ? b - inv(b % a, a) * b / a : 1;
}
long long gcd(long long a, long long b, long long& x, long long& y) {
  if (a == 0) {
    x = 0;
    y = 1;
    return b;
  }
  long long x1, y1;
  long long d = gcd(b % a, a, x1, y1);
  x = y1 - (b / a) * x1;
  y = x1;
  return d;
}
long long distsq(long long x1, long long y1, long long x2, long long y2) {
  return (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1);
}
const int N = 200001;
long long n, m, k, t, u, v;
string s;
unordered_set<int> ks;
unordered_map<int, vector<int>> g;
int visited[N];
long long tosink[N];
long long tosource[N];
void bfs(int start, long long arr[]) {
  for (int i = 0; i < n + 1; i++) arr[i] = -1;
  deque<int> q;
  q.push_back(start);
  arr[start] = 0;
  while (!q.empty()) {
    int n = q.size();
    for (int i = 0; i < (n); i++) {
      int curr = q.front();
      q.pop_front();
      for (int c : g[curr]) {
        if (arr[c] == -1) {
          arr[c] = arr[curr] + 1;
          q.push_back(c);
        }
      }
    }
  }
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m >> k;
  for (int i = 0; i < (k); i++) {
    cin >> u;
    ks.emplace(u);
  }
  for (int i = 0; i < (m); i++) {
    cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  bfs(1, tosource);
  bfs(n, tosink);
  vector<pair<int, int>> tok;
  map<int, unordered_set<int>> towardssink;
  for (auto& p : ks) {
    tok.push_back(make_pair(tosource[p], p));
    towardssink[-tosink[p]].emplace(p);
  }
  sort((tok).begin(), (tok).end());
  long long best = 0;
  for (auto& p : tok) {
    long long mintosource = p.first;
    long long node = p.second;
    towardssink[-tosink[node]].erase(node);
    if (towardssink[-tosink[node]].empty()) {
      towardssink.erase(-tosink[node]);
    }
    if (towardssink.empty()) break;
    auto& pr = *towardssink.begin();
    long long mxtosink = -pr.first;
    long long curr = 1;
    curr = curr + mintosource + min(tosink[node], mxtosink);
    best = max(best, curr);
  }
  long long normaldist = tosink[1];
  if (best < normaldist) {
    cout << best << endl;
  } else {
    cout << normaldist << endl;
  }
}
