#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int C = 26;
void add(int &x, int y) {
  x += y;
  while (x >= MOD) x -= MOD;
  while (x < 0) x += MOD;
}
int fix(int x) {
  while (x >= MOD) x -= MOD;
  while (x < 0) x += MOD;
  return x;
}
int pw(int a, int b) {
  int ret = 1;
  while (b) {
    if (b & 1) ret = 1ll * ret * a % MOD;
    b >>= 1;
    a = 1ll * a * a % MOD;
  }
  return ret;
}
const int MAXN = 1e5 + 10;
vector<int> adj[MAXN];
bool gone[MAXN], banned[MAXN];
int n, m, k;
bool cmp(pair<long long, long long> a, pair<long long, long long> b) {
  return a.first * b.second < b.first * a.second;
}
struct cmp2 {
  bool operator()(pair<int, pair<long long, long long>> a,
                  pair<int, pair<long long, long long>> b) {
    return cmp(b.second, a.second);
  }
};
long long vec[MAXN], sec[MAXN];
pair<long long, long long> go(pair<long long, long long> best) {
  memcpy(gone, banned, sizeof(gone));
  priority_queue<pair<int, pair<long long, long long>>,
                 vector<pair<int, pair<long long, long long>>>, cmp2>
      pq;
  for (int v = 0; v < n; v++) {
    if (gone[v]) continue;
    vec[v] = adj[v].size();
    sec[v] = 0;
    for (int u : adj[v])
      if (!gone[u]) ++sec[v];
    pq.push({v, {sec[v], vec[v]}});
  }
  pair<long long, long long> ret = {0, 1};
  while (!pq.empty()) {
    auto [v, pp] = pq.top();
    if (pp != make_pair(sec[v], vec[v])) {
      pq.pop();
      continue;
    }
    if (cmp(ret, pp)) ret = pp;
    if (!cmp(pp, best)) {
      cerr << "ratio: " << (long double)pp.first / pp.second << "\n";
      vector<int> ans;
      while (!pq.empty()) {
        auto [u, pp2] = pq.top();
        pq.pop();
        if (pp2 == make_pair(sec[u], vec[u])) ans.push_back(u);
      }
      sort(ans.begin(), ans.end());
      cout << ans.size() << "\n";
      for (int x : ans) {
        cout << x + 1 << " ";
      }
      cout << "\n";
      exit(0);
    }
    pq.pop();
    gone[v] = 1;
    for (int u : adj[v]) {
      if (gone[u]) continue;
      --sec[u];
      pq.push({u, {sec[u], vec[u]}});
    }
  }
  return ret;
}
void solve() {
  cin >> n >> m >> k;
  for (int i = 0; i < k; i++) {
    int a;
    cin >> a;
    --a;
    banned[a] = 1;
  }
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    --a;
    --b;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
  pair<long long, long long> best = go({2, 1});
  go(best);
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int te = 1;
  for (int w = 1; w <= te; w++) {
    solve();
  }
  return 0;
}
