import sys,math,itertools
from collections import Counter,deque,defaultdict
from bisect import bisect_left,bisect_right 
from heapq import heappop,heappush,heapify
mod = 10**9+7
INF = float('inf')
def inp(): return int(sys.stdin.readline())
def inpl(): return list(map(int, sys.stdin.readline().split()))
def inpl_1(): return list(map(lambda x:int(x)-1, sys.stdin.readline().split()))
def inps(): return sys.stdin.readline()
def inpsl(x): tmp = sys.stdin.readline(); return list(tmp[:x])
def err(x): print(x); exit()

n,m = inpl()
a = inpl()
g = [[] for _ in range(n)]
ny = [0]*n
for _ in range(m):
    u,v = inpl_1()
    if a[u] == a[v]: continue
    if a[u] > a[v]: u,v = v,u
    g[u].append(v)
    ny[v] += 1
k = inp()
b = [0]*n
for x in inpl():
    b[x-1] = 1
q = deque([])
seen = [0]*n
res = []
for i,x in enumerate(ny):
    if x == 0:
        q.append(i)
        seen[i] = 1
while q:
    u = q.popleft()
    if b[u]: 
        res.append(u+1)
    for v in g[u]:
        if seen[v]: continue
        b[v] ^= b[u]
        ny[v] -= 1
        if ny[v] == 0:
            q.append(v)
            seen[v] = 1
print(len(res))
for x in res:
    print(x)