#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <utility>
#include <tuple>
#include <cmath>
#include <numeric>
#include <set>
#include <map>
#include <array>
#include <complex>
#include <iomanip>
#include <cassert>
#include <random>
using ll = long long;
using std::cin;
using std::cout;
using std::endl;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int inf = (int)1e9 + 7;
const long long INF = 1LL << 60;

void solve()
{
  int n, m; cin >> n >> m;
  std::vector<std::pair<int , int>> vp(n);
  std::vector<int> a(n);
  for (int i = 0; i < n; ++i)
  {
    cin >> vp[i].first;
    a[i] = vp[i].first;
    vp[i].second = i;
  }
  std::sort(vp.begin(), vp.end());
  std::vector<std::vector<int>> g(n);
  for (int i = 0; i < m; ++i)
  {
    int u, v; cin >> u >> v;
    u -= 1, v -= 1;
    g[u].emplace_back(v);
    g[v].emplace_back(u);
  }
  int k; cin >> k;
  std::vector<int> on(n);
  for (int i = 0; i < k; ++i)
  {
    int b; cin >> b;
    b -= 1;
    on[b] = 1;
  }
  std::vector<int> res;
  for(const auto [_, idx] : vp)
  {
    if(on[idx])
    {
      res.emplace_back(idx);
      for(const auto nxt : g[idx])
      {
        if(a[idx] < a[nxt])
        {
          on[nxt] ^= 1;
        }
      }
      on[idx] ^= 1;
    }
  }
  for (int i = 0; i < n; ++i)
  {
    if(on[i])
    {
      cout << -1 << "\n";
      return;
    }
  }
  cout << res.size() << "\n";
  for (int i = 0; i < (int)res.size(); ++i)
  {
    cout << res[i] + 1 << "\n";
  }
}
int main()
{
  std::cin.tie(nullptr);
  std::ios::sync_with_stdio(false);

  int kkt = 1;
  //cin >> kkt;
  while(kkt--)
    solve();
  return 0;
}