#include "bits/stdc++.h"
//#include "atcoder/all"
using namespace std;
//using namespace atcoder;
//using mint = modint1000000007;
//const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
vector<int>to[100005];
std::vector<int>topological_sort(int V) {
	std::vector<int>h(V);
	for (int i = 0; i < V; ++i) for (auto e : to[i]) ++h[e];
	std::stack<int>st;
	std::vector<int>ans;
	for (int i = 0; i < V; ++i) if (h[i] == 0) st.push(i);
	while (!st.empty()) {
		int v = st.top(); st.pop();
		ans.push_back(v);
		for (auto u : to[v]) {
			--h[u];
			if (h[u] == 0) st.push(u);
		}
	}
	return ans;
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n, m;
	cin >> n >> m;
	vector<int>a(n);
	rep(i, n) cin >> a[i];
	rep(i, m) {
		int u, v;
		cin >> u >> v;
		u--; v--;
		int x = a[u];
		int y = a[v];
		if (x > y) to[v].push_back(u);
		else if (x < y) to[u].push_back(v);
	}
	vector<bool>b(n);//false消灯
	int k;
	cin >> k;
	rep(i, k) {
		int num;
		cin >> num;
		num--;
		b[num] = true;
	}
	auto sv = topological_sort(n);
	vector<int>vans;
	rep(i, n) {
		if (!b[sv[i]]) continue;
		b[sv[i]] = false;
		vans.push_back(sv[i] + 1);
		for (auto v : to[sv[i]]) b[v] = !b[v];
	}
	cout << vans.size() << endl;
	rep(i, vans.size()) cout << vans[i] << endl;
	return 0;
}