#include <bits/stdc++.h>
using namespace std;
const long long maxn = 100100;
long long n, m, k;
vector<long long> g[maxn];
long long mark[maxn];
long long d[maxn];
vector<long long> q;
bool check(long long x, bool print = false) {
  for (long long i = 0; i < n; i++)
    if (mark[i] != 1) mark[i] = 0;
  q.resize(0);
  for (long long i = 0; i < n; i++) d[i] = 0;
  for (long long i = 0; i < n; i++)
    for (long long u : g[i])
      if (!mark[u]) d[i]++;
  for (long long i = 0; i < n; i++)
    if (!mark[i] and d[i] * 1000000000 < g[i].size() * x)
      q.push_back(i), mark[i] = 2;
  for (long long i = 0; i < q.size(); i++) {
    long long v = q[i];
    mark[v] = 2;
    for (long long u : g[v])
      if (!mark[u]) {
        d[u]--;
        if (d[u] * 1000000000 < g[u].size() * x and !mark[u])
          q.push_back(u), mark[u] = 2;
      }
  }
  long long cnt = 0;
  for (long long i = 0; i < n; i++) cnt += !mark[i];
  if (print) {
    cout << cnt << endl;
    for (long long i = 0; i < n; i++)
      if (!mark[i]) cout << i + 1 << " ";
    cout << endl;
  }
  return cnt;
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m >> k;
  for (long long v, i = 0; i < k; i++) {
    cin >> v;
    v--;
    mark[v] = 1;
  }
  for (long long v, u, i = 0; i < m; i++) {
    cin >> v >> u;
    v--, u--;
    g[v].push_back(u);
    g[u].push_back(v);
  }
  for (long long i = 0; i < n; i++)
    if (!g[i].size()) mark[i] = 1;
  long long l = 0, r = 1000000000 + 1, mid;
  for (long long c = 100; c--;) {
    mid = (l + r) / 2;
    if (check(mid))
      l = mid;
    else
      r = mid;
  }
  check(l, 1);
  return 0;
}
