n,m=map(int,input().split())
a=[-1]+list(map(int,input().split()))
root=[[] for i in range(n+1)]
rootr=[[] for i in range(n+1)]
import sys
sys.setrecursionlimit(10**9)
for i in range(m):
    v,u=map(int,input().split())
    if a[v]>a[u]:
        root[u].append(v)
        rootr[v].append(u)
    elif a[u]>a[v]:
        root[v].append(u)
        rootr[u].append(v)
memo=[-1]*(n+1)
light=[0]*(n+1)
ans=[]
k=int(input())
b=list(map(int,input().split()))
for x in b:light[x]=1
def f(x):
    if memo[x]!=-1:return memo[x]
    res=0
    for nod in rootr[x]:
        res+=f(nod)
    if light[x]^(res%2)==1:
        res+=1
        ans.append(x)
    memo[x]=res
    return res
def g(x):
    if len(root[x])==0:f(x)
    else:
        for nod in root[x]:g(nod)

for i in range(1,n+1):
    if memo[i]==-1:g(i)
print(len(ans))
for x in ans:
    print(x)