//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using ll = int64_t;
using ull = uint64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQG = priority_queue<T, vector<T>, greater<T>>;
const int INF = 0xccccccc;
const ll LINF = 0xcccccccccccccccLL;
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);}
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);}
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) { return is >> p.first >> p.second;}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) { return os << p.first << ' ' << p.second;}



//head



int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  vi a(n);
  rep(i, n) cin >> a[i];
  vi ids(n);
  iota(all(ids), 0);
  sort(all(ids), [&](int i, int j){return a[i] < a[j];});
  vvi G(n);
  rep(i, m) {
    int a, b;
    cin >> a >> b;
    a--; b--;
    G[a].emplace_back(b);
    G[b].emplace_back(a);
  }
  vi light(n);
  int k;
  cin >> k;
  rep(i, k) {
    int a;
    cin >> a;
    a--;
    light[a] = 1;
  }
  int z = 0;
  vi ans;
  for(auto id:ids) {
    if(!light[id]) continue;
    z++;
    ans.emplace_back(id+1);
    for(auto ne:G[id]) if(a[ne] > a[id]) light[ne] ^= 1;
  }
  cout << z << endl;
  for(auto x:ans) cout << x << '\n';
}