//dijkstra
//TLE
#include <iostream>
#include <algorithm>
#include <atcoder/all>
#include <queue>
using namespace std;
using namespace atcoder;
using ll = long long;
//#define endl "\n";
const long long INF = 1000000000000000000;

ll N, M, K, A[100009], visited[100009];
vector<vector<ll>> preG;

//dijkstra
struct edge{
  ll pre, to;
  ll cost;
};
vector<vector<edge>> G;
vector<ll> dijkstra(int start = 0) {
  int N = G.size();
  vector<ll> dist(N, INF);
  using classPQ = pair<ll, ll>;
  priority_queue<classPQ, vector<classPQ>, greater<classPQ>> que;
  que.emplace(0, start);
  dist[start] = 0;
  while(!que.empty()){
    auto [d, c] = que.top();
    que.pop();
    
    if(dist[c] != d) continue;
    for(auto& e : G[c]){
      if(d + e.cost < dist[e.to]){
        dist[e.to] = d + e.cost;
        que.emplace(dist[e.to], e.to);
      }
    }
  }
  return dist;
}

int main(){
  cin >> N >> M;
  preG.resize(N + 1);
  G.resize(N + 1);
  for(int i = 0; i < M; i++){
    ll u, v;
    cin >> u >> v;
    preG[u].push_back(v);
    preG[v].push_back(u);
  }
  cin >> K;
  for(int i = 0; i < K; i++){
    ll a;
    cin >> a;
    A[a] = 1;
  }
  
  //空き頂点間を探索
  int idx = 0;
  for(int i = 1; i <= N; i++){
    if(A[i] == 0){
      idx++;
      queue<pair<ll,ll>> que;
      visited[i] = idx;
      que.push({i, 0});
      while(!que.empty()){
        auto [pos, cnt] = que.front(); que.pop();
        for(auto to: preG[pos]){
          if(visited[to] < idx){
            if(A[to] == 1 && cnt < 4){
              visited[to] = idx;
              que.push({to, cnt + 1});
            }
            if(A[to] == 0){
              visited[to] = idx;
              G[i].push_back(edge{i, to, cnt + 1});
              G[to].push_back(edge{to, i, cnt + 1});
            }
          }
        }
      }
    }
  }
  auto dist = dijkstra(1);
  if(dist[N] == INF) cout << -1 << endl;
  else cout << dist[N] << endl;
  return 0;
}