import sys
from heapq import heappop,heappush,heapify
sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


N,M = MI()
A = [0]+LI()
Graph = [[] for _ in range(N+1)]
for _ in range(M):
    u,v = MI()
    Graph[u].append(v)
    Graph[v].append(u)
K = I()
B = LI()

C = []
is_light = [0]*(N+1)
for b in B:
    heappush(C,(A[b],b))
    is_light[b] = 1

ANS = []
while C:
    a,u = heappop(C)
    if not is_light[u]:
        continue
    ANS.append(u)
    is_light[u] = 0
    for v in Graph[u]:
        if a < A[v]:
            is_light[v] ^= 1
            if is_light[v]:
                heappush(C,(A[v],v))

print(len(ANS))
print(*ANS,sep='\n')