N, M = map(int, input().split())
L = [0] * N
A = list(map(int, input().split()))
V = [i for i in range(N)]
V.sort(key = lambda x: A[x])
adj = [[] for i in range(N)]
for i in range(M):
    u, v = map(int, input().split())
    u -= 1
    v -= 1
    adj[u].append(v)
    adj[v].append(u)
K = int(input())
B = list(map(int, input().split()))
for b in B:
    L[b - 1] = 1

op = []
for v in V:
    if L[v] == 0:
        continue
    L[v] = 0
    op.append(v + 1)
    for nv in adj[v]:
        if A[nv] > A[v]:
            L[nv] ^= 1


if sum(L) != 0:
    print(-1)
else:
    print(len(op))
    print(*op, sep = "\n")