import sys
input = sys.stdin.readline

N, M = map(int, input().split())
A = list(map(int, input().split()))
G = [[] for _ in range(N)]

for _ in range(M):
    u, v = map(int, input().split())
    G[u-1].append(v-1)
    G[v-1].append(u-1)

K = int(input())
B = list(map(int, input().split()))
flag = [False]*N

for Bi in B:
    flag[Bi-1] = True

Ai = [(A[i], i) for i in range(N)]
Ai.sort()
ans = []

for _, v in Ai:
    if flag[v]:
        ans.append(v+1)
        
        for nv in G[v]:
            if A[v]<A[nv]:
                flag[nv] ^= True

print(len(ans))

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