# もう一度やる
# 入次数0の頂点から調べて、スイッチを押していく
# その頂点を調べて、スイッチを押したらnxt頂点のonoffも調整
# そうしたらnxt頂点の次数を1つ減らす、次数が0になったら調べるリストに入れる

N, M = map(int, input().split())
A = [0]+list(map(int, input().split()))
edges = [[] for i in range(N+1)]
inward = [0]*(N+1)
for i in range(M):
    u, v = map(int, input().split())
    if A[u] < A[v]:
        edges[u].append(v)
        inward[v] += 1
    elif A[u] > A[v]:
        edges[v].append(u)
        inward[u] += 1

K = int(input())
B = list(map(int, input().split()))

on_off = [0]*(N+1)
for b in B:
    on_off[b] = 1
        
from collections import deque
que = deque()
for i in range(1, N+1):
    if inward[i] == 0:
        que.append(i)

ans = []
while que:
    current = que.popleft()
    
    if on_off[current] == 0:
        for nxt in edges[current]:
            inward[nxt] -= 1
            if inward[nxt] == 0:
                que.append(nxt)
    elif on_off[current] == 1:
        ans.append(current)
        for nxt in edges[current]:
            on_off[nxt] ^= 1
            inward[nxt] -= 1
            if inward[nxt] == 0:
                que.append(nxt)
    
print(len(ans))
for a in ans:
    print(a)