#include <bits/stdc++.h>
using namespace std;
const int MOD = 1000000007;
const int INF = 0x3f3f3f3f;
const int MAXN = 1010;
int N, M, K;
vector<int> path[100005];
bool is_fort[100005];
int degree[100005];
int self_degree[100005];
int t_stamp[100005];
priority_queue<pair<double, pair<int, int> >,
               vector<pair<double, pair<int, int> > >,
               greater<pair<double, pair<int, int> > > >
    railgun;
double best_ans;
int best_delete_num;
bool deleted[100005];
vector<int> deleted_set;
int main() {
  ios_base::sync_with_stdio(false);
  cin.sync_with_stdio(false);
  cout.sync_with_stdio(false);
  cin >> N >> M >> K;
  int t;
  for (int i = 0; i < K; i++) {
    cin >> t;
    is_fort[t] = true;
  }
  int u, v;
  for (int i = 0; i < M; i++) {
    cin >> u >> v;
    path[u].push_back(v);
    path[v].push_back(u);
    degree[u]++;
    degree[v]++;
    if (!is_fort[v]) self_degree[u]++;
    if (!is_fort[u]) self_degree[v]++;
  }
  for (int i = 1; i <= N; i++) {
    if (!is_fort[i]) {
      railgun.push(make_pair((double)self_degree[i] / degree[i],
                             make_pair(i, ++t_stamp[i])));
    }
  }
  while (!railgun.empty()) {
    pair<double, pair<int, int> > tpair = railgun.top();
    int tid = tpair.second.first;
    int ttime = tpair.second.second;
    double tprob = tpair.first;
    railgun.pop();
    if (ttime == t_stamp[tid]) {
      if (tprob > best_ans) {
        best_ans = tprob;
        best_delete_num = deleted_set.size();
      }
      deleted_set.push_back(tid);
      deleted[tid] = true;
      for (auto k : path[tid]) {
        if (!deleted[k] && !is_fort[k]) {
          self_degree[k]--;
          railgun.push(make_pair((double)self_degree[k] / degree[k],
                                 make_pair(k, ++t_stamp[k])));
        }
      }
    }
  }
  for (int i = 0; i < best_delete_num; i++) {
    is_fort[deleted_set[i]] = true;
  }
  cout << N - K - best_delete_num << endl;
  for (int i = 1; i <= N; i++) {
    if (!is_fort[i]) {
      cout << i << " ";
    }
  }
  return 0;
}
