from heapq import heapify, heappop, heappush
N,M = map(int,input().split())
A = list(map(int,input().split()))
G = [[] for _ in range(N)]
for i in range(M):
    u,v = map(int,input().split())
    u-=1;v-=1
    G[u].append(v)
    G[v].append(u)
K = int(input())
B = list(map(int,input().split()))
B = [b-1 for b in B]
Status = [0]*N
HQ = []
for b in B:
    Status[b] = 1
for i in range(N):
    if Status[i] == 1:
        heappush(HQ,(A[i],i)) #value, index

ret = []
while HQ:
    val,idx = heappop(HQ)
    if Status[idx] == 0: #消灯していたらスキップ
        continue
    Status[idx] = 0
    ret.append(idx+1) #1index
    for adj in G[idx]:
        if A[adj] > A[idx]:
            if Status[adj] == 0:
                Status[adj] = 1
                heappush(HQ,(A[adj],adj))
            else:
                Status[adj] = 0
    
print(len(ret))
print(*ret,sep="\n")