n,m=map(int,input().split())
a=list(map(int,input().split()))
path=[[] for _ in range(n)]
for i in range(m):
    c,d=map(int,input().split())
    if a[c-1]<a[d-1]:path[c-1].append(d-1)
    if a[d-1]<a[c-1]:path[d-1].append(c-1)
seen=[False]*n
k=int(input())
b=list(map(int,input().split()))
for i in b:seen[i-1]=True
num=[[a[_],_] for _ in range(n)]
num.sort(key=lambda x: x[0])
ans=[]
for i in range(n):
    ind=num[i][1]
    if seen[ind]:
        ans.append(ind+1)
        for j in range(len(path[ind])):
            if seen[path[ind][j]]:seen[path[ind][j]]=False
            else:seen[path[ind][j]]=True
print(len(ans))
for i in ans:print(i)