N,M=map(int, input().split())
A=list(map(int, input().split()))
G=[[]for i in range(N)]
deg=[0]*N
for i in range(M):
  a,b=map(int, input().split())
  a-=1
  b-=1
  if A[a]<A[b]:
    G[a].append(b)
    deg[b]+=1
  if A[a]>A[b]:
    G[b].append(a)
    deg[a]+=1
V=N
# V:頂点数
# G[v] = [w, ...]:有向グラフ上の頂点vから到達できる頂点w
# deg[v]:頂点vに到達できる頂点の数
from collections import deque
ans = list(v for v in range(V) if deg[v] == 0)
deq = deque(ans)
used = [0] * V
while deq:
  v=deq.popleft()
  for t in G[v]:
    deg[t]-=1
    if deg[t]==0:
      deq.append(t)
      ans.append(t)

L=[0]*N
K=int(input())
B=list(map(int, input().split()))
for b in B:
  L[b-1]=1
F=[]
for i in ans:
  if L[i]==1:
    F.append(i+1)
    for nex in G[i]:
      L[nex]=1-L[nex]
print(len(F))
for f in F:
  print(f)