N, M = map(int, input().split())
As = list(map(int, input().split()))
adj = [[] for _ in range(N)]
for _ in range(M):
    u, v = map(int, input().split())
    u -= 1
    v -= 1
    adj[u].append(v)
    adj[v].append(u)
K = int(input())
on = [False] * N
for B in map(int, input().split()):
    B -= 1
    on[B] = True

iAs = sorted(enumerate(As), key=lambda t: t[1])

answer = []
for i, A in iAs:
    if on[i] == True:
        answer.append(i)
        for nv in adj[i]:
            if As[nv] > As[i]:
                on[nv] = not on[nv]

print(len(answer))
print(*[a + 1 for a in answer], sep='\n')