from collections import defaultdict
N, M = map(int, input().split())
A = [0]+list(map(int, input().split()))
task = [[0, 0]]+[[A[i], i] for i in range(1, N+1)]
task.sort()
Edges = defaultdict(set)
for _ in range(M):
    u, v = map(int, input().split())
    Edges[u].add(v)
    Edges[v].add(u)
K = int(input())
B = set(map(int, input().split()))
state = [int(i in B) for i in range(N+1)]
ans = []

for a, v in task:
    if not state[v]:
        continue
    state[v] = 0
    ans.append(v)
    for e in Edges[v]:
        if A[e] > a:
            state[e] ^= 1

if sum(state):
    print(-1)
else:
    print(len(ans))
    print(*ans, sep='\n')