N,M=map(int,input().split())
A=[0]+list(map(int,input().split()))
E=[[] for i in range(N+1)]

for i in range(M):
    u,v=map(int,input().split())
    if A[u]>A[v]:
        E[v].append(u)
    elif A[v]>A[u]:
        E[u].append(v)

K=int(input())
B=list(map(int,input().split()))
LIGHT=[0]*(N+1)
for b in B:
    LIGHT[b]=1

DEGIN=[0]*(N+1)
for i in range(1,N+1):
    for k in E[i]:
        DEGIN[k]+=1

Q=[]
ANS=[]
for i in range(1,N+1):
    if DEGIN[i]==0:
        if LIGHT[i]==1:
            Q.append((i,1))
            ANS.append(i)
        else:
            Q.append((i,0))
            
while Q:
    #print(Q)
    now,t=Q.pop()
    for to in E[now]:
        if t!=LIGHT[to]:
            ANS.append(to)    
        Q.append((to,LIGHT[to]))

print(len(ANS))
print("\n".join(map(str,ANS)))