from collections import defaultdict, deque

n, m = map(int, input().split())
A = list(map(int, input().split()))
IN = [0 for _ in range(n)]
G = defaultdict(list)
for _ in range(m):
    u, v = map(int, input().split())
    u -= 1
    v -= 1
    if A[u] > A[v]:
        G[v].append(u)
        IN[u] += 1
    elif A[u] < A[v]:
        G[u].append(v)
        IN[v] += 1
Que = deque([i for i in range(n) if IN[i] == 0])
k = int(input())
B = list(map(int, input().split()))
L = [0 for _ in range(n)]
for i in range(k):
    L[B[i] - 1] = 1
ANS = []
while Que:
    idx, on = Que.popleft()
    if L[idx] == 1:
        ANS.append(idx + 1)
    for nidx in G[idx]:
        IN[nidx] -= 1
        L[nidx] ^= L[idx]
        if IN[nidx] == 0:
            Que.append((nidx, on))
    L[idx] = 0
print(len(ANS))
print(*ANS, sep='\n')