#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0), cin.tie(0);
  int n, m, k;
  cin >> n >> m >> k;
  vector<bool> bad(n);
  for (int x; k--;) {
    cin >> x;
    bad[x - 1] = true;
  }
  vector<vector<int>> adj(n);
  for (int i = 0, u, v; i < m; ++i) {
    cin >> u >> v;
    --u, --v;
    adj[u].push_back(v);
    adj[v].push_back(u);
  }
  auto f = [&](long double r) {
    vector<int> cnt(n);
    for (int u = 0; u < n; ++u)
      for (auto v : adj[u])
        if (!bad[u] && !bad[v]) ++cnt[u];
    queue<int> q;
    vector<bool> mark(n);
    for (int i = 0; i < n; ++i)
      if (!bad[i] && (long double)cnt[i] / adj[i].size() < r) {
        mark[i] = true;
        q.push(i);
      }
    while (!q.empty()) {
      int u = q.front();
      q.pop();
      for (auto v : adj[u])
        if (!bad[v] && !mark[v] && (long double)--cnt[v] / adj[v].size() < r) {
          mark[v] = true;
          q.push(v);
        }
    }
    vector<int> ans;
    for (int i = 0; i < n; ++i)
      if (!bad[i] && !mark[i]) ans.push_back(i);
    return ans;
  };
  long double l = 0, r = 1;
  for (int it = 100; it--;) {
    long double md = (l + r) / 2;
    if (f(md).empty())
      r = md;
    else
      l = md;
  }
  auto ans = f(l);
  cout << ans.size() << "\n";
  for (auto &i : ans) cout << i + 1 << " \n"[&i == &ans.back()];
  return 0;
}
