N,M=map(int,input().split())
A=[-1]+list(map(int,input().split()))
AS= [[0] * 2 for i in range(N+1)]
for i,a in enumerate(A):
    AS[i][0]=i
    AS[i][1]=a

AS = sorted(AS, key=lambda x: x[1])

L = []
for i in range(N+1):
    L.append([])
for i in range(M):
    v,u = map(int,input().split())
    L[v].append(u)
    L[u].append(v)
K = int(input())
B=list(map(int,input().split()))
LAMP=[False]*(N+1)
for b in B:
    LAMP[b]=True
ANS = []
for i,a in AS:
    if LAMP[i]:
        ANS.append(i)
        for l in L[i]:
            if A[i]<A[l]:
                LAMP[l]=not LAMP[l]
print(len(ANS))
for ans in ANS:
    print(ans)