import java.io.*; import java.util.*; import java.util.stream.*; public class Main { public static void main(String[] args) throws Exception { Scanner sc = new Scanner(); int n = sc.nextInt(); int m = sc.nextInt(); int[] values = new int[n]; ArrayList> graph = new ArrayList<>(); for (int i = 0; i < n; i++) { values[i] = sc.nextInt(); graph.add(new ArrayList<>()); } for (int i = 0; i < m; i++) { int a = sc.nextInt() - 1; int b = sc.nextInt() - 1; if (values[a] < values[b]) { graph.get(a).add(b); } else if (values[a] > values[b]) { graph.get(b).add(a); } } boolean[] isOn = new boolean[n]; int k = sc.nextInt(); while (k-- > 0) { isOn[sc.nextInt() - 1] = true; } ArrayList ans = new ArrayList<>(); for (int i = 0; i < n; i++) { if (isOn[i]) { ans.add(i + 1); for (int x : graph.get(i)) { isOn[x] ^= true; } } } System.out.println(ans.size()); System.out.println(ans.stream().map(x -> x.toString()).collect(Collectors.joining("\n"))); } } class Utilities { static String arrayToLineString(Object[] arr) { return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n")); } static String arrayToLineString(int[] arr) { return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new)); } } class Scanner { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); StringTokenizer st = new StringTokenizer(""); StringBuilder sb = new StringBuilder(); public Scanner() throws Exception { } public int nextInt() throws Exception { return Integer.parseInt(next()); } public long nextLong() throws Exception { return Long.parseLong(next()); } public double nextDouble() throws Exception { return Double.parseDouble(next()); } public int[] nextIntArray() throws Exception { return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray(); } public String next() throws Exception { while (!st.hasMoreTokens()) { st = new StringTokenizer(br.readLine()); } return st.nextToken(); } }