import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.PriorityQueue;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] sa = br.readLine().split(" ");
		int n = Integer.parseInt(sa[0]);
		int m = Integer.parseInt(sa[1]);

		sa = br.readLine().split(" ");
		Obj[] arr = new Obj[n];
		PriorityQueue<Obj> que = new PriorityQueue<>((o1, o2) -> o1.a - o2.a);
		for (int i = 0; i < n; i++) {
			Obj o = new Obj();
			o.i = i;
			o.a = Integer.parseInt(sa[i]);
			que.add(o);
			arr[i] = o;
		}

		List<List<Integer>> list = new ArrayList<>(n);
		for (int i = 0; i < n; i++) {
			list.add(new ArrayList<>());
		}
		for (int i = 0; i < m; i++) {
			sa = br.readLine().split(" ");
			int u = Integer.parseInt(sa[0]) - 1;
			int v = Integer.parseInt(sa[1]) - 1;
			list.get(u).add(v);
			list.get(v).add(u);
		}

		int k = Integer.parseInt(br.readLine());
		boolean[] p = new boolean[n];
		sa = br.readLine().split(" ");
		for (int i = 0; i < k; i++) {
			int b = Integer.parseInt(sa[i]) - 1;
			p[b] = true;
		}
		br.close();

		List<Integer> ans = new ArrayList<>();
		while (!que.isEmpty()) {
			Obj o = que.poll();
			if (!p[o.i]) {
				continue;
			}
			ans.add(o.i + 1);
			p[o.i] = false;
			for (int i : list.get(o.i)) {
				if (arr[i].a > o.a) {
					p[i] = !p[i];
				}
			}
		}

		PrintWriter pw = new PrintWriter(System.out);
		pw.println(ans.size());
		for (int i : ans) {
			pw.println(i);
		}
		pw.flush();
	}

	static class Obj {
		int i, a;
	}
}