#include <bits/stdc++.h>
//#include<boost/multiprecision/cpp_int.hpp>
//#include<boost/multiprecision/cpp_dec_float.hpp>
//#include <atcoder/all>
#define rep(i, a) for (int i = (int)0; i < (int)a; ++i)
#define rrep(i, a) for (int i = (int)a; i >-1; --i)
#define REP(i, a, b) for (int i = (int)a; i < (int)b; ++i)
#define RREP(i, a, b) for (int i = (int)a; i > b; --i)
#define repl(i, a) for (ll i = (ll)0; i < (ll)a; ++i)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define popcount __builtin_popcount
#define popcountll __builtin_popcountll
#define fi first
#define se second
using ll = long long;
constexpr ll mod = 1e9 + 7;
constexpr ll mod_998244353 = 998244353;
constexpr ll INF = 1LL << 60;

// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")

//using lll=boost::multiprecision::cpp_int;
//using Double=boost::multiprecision::number<boost::multiprecision::cpp_dec_float<128>>;//仮数部が1024桁
template <class T>
inline bool chmin(T &a, T b)
{
	if (a > b)
	{
		a = b;
		return true;
	}
	return false;
}
template <class T>
inline bool chmax(T &a, T b)
{
	if (a < b)
	{
		a = b;
		return true;
	}
	return false;
}

ll mypow(ll x, ll n, const ll &p = -1)
{ //x^nをmodで割った余り

	if (p != -1)
	{
		x =(x%p+p)%p;
	}
	ll ret = 1;
	while (n > 0)
	{
		if (n & 1)
		{
			if (p != -1)
				ret = (ret * x) % p;
			else
				ret *= x;
		}
		if (p != -1)
			x = (x * x) % p;
		else
			x *= x;
		n >>= 1;
	}
	return ret;
}

using namespace std;
//using namespace atcoder;

using P=pair<int,int>;
void solve()
{	
	int n,m;
	cin>>n>>m;
	vector<ll>a(n);
	rep(i,n)cin>>a[i];
	vector<vector<int>>g(n);
	vector<int>cnt(n);
	rep(i,m){
		int u,v;
		cin>>u>>v;
		u--;v--;
		if(a[u]<a[v])g[u].eb(v),cnt[v]++;
		else if(a[u]>a[v])g[v].eb(u),cnt[u]++;
	}
	int k;
	cin>>k;
	vector<int>b(n);
	rep(i,k){
		int x;
		cin>>x;
		x--;
		b[x]=true;
	}

	queue<int>q;
	rep(i,n){
		if(cnt[i]==0){
			q.emplace(i);
		}
	}
	vector<int>ans;
	while(!q.empty()){
		int v=q.front();
		q.pop();

		for(auto x:g[v]){
			cnt[x]--;
			if(!cnt[x]){
				q.emplace(x);
			}
			if(b[v]){
				b[x]^=1;
			}
		}
		if(b[v]){
			ans.eb(v+1);
			b[v]=false;
		}
	}
	rep(i,n){
		assert(!b[i]);
	}
	cout<<ans.size()<<"\n";
	rep(i,ans.size()){
		cout<<ans[i]<<"\n";
	}
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout << fixed << setprecision(15);
	solve();
	return 0;
}