N, M = map(int, input().split())
A = [int(s) for s in input().split()]

X = [[] for _ in range(N)]

for i in range(M):
    U, V = map(int, input().split())
    U -= 1
    V -= 1
    if A[U] < A[V]:
        X[U].append(V)
    if A[V] < A[U]:
        X[V].append(U)

K = int(input())
B = [int(s) for s in input().split()]

L = [False]*N

for i in B:
    L[i - 1] = True

F = sorted([(A[i], i) for i in range(N)])

Y = []

for _, i in F:
    if L[i]:
        Y.append(i+1)
        for j in X[i]:
            L[j] = not L[j]


print(len(Y))
for i in range(len(Y)):
    print(Y[i])