import sys
from collections import deque, Counter
input = lambda: sys.stdin.readline().rstrip()
ii = lambda: int(input())
mi = lambda: map(int, input().split())
li = lambda: list(mi())
inf = 2 ** 63 - 1
mod = 998244353

import heapq
class Heap():
    def __init__(self, maxi = False):
        self.sum = 0
        self.al = []
        self.maxi = maxi
        self.len = 0

    def __len__(self):
        return len(self.al)

    def add(self, x):
        if self.maxi:
            heapq.heappush(self.al, -x)
        else:
            heapq.heappush(self.al, x)
    
    def pop(self):
        if self.maxi:
            now = heapq.heappop(self.al)
            return -now
        else:
            now = heapq.heappop(self.al)
            return now

    def top(self):
        now = self.pop()
        self.add(now)
        return now

n, m = mi()
a = li()

graph = [[] for _ in range(n)]

for _ in range(m):
    u, v = mi()
    u -= 1; v -= 1
    graph[u].append(v)
    graph[v].append(u)

k = li()
b = li()
H = Heap()
color = [0] * n
for v in b:
    color[v - 1] = 1
    H.add((a[v - 1], v - 1))
ans = []
while H:
    nowa, now = H.pop()
    if color[now] == 0:
        continue
    color[now] = 0
    ans.append(now + 1)
    for to in graph[now]:
        if a[now] < a[to]:
            color[to] ^= 1
            if color[to] == 1:
                H.add((a[to], to))

print(len(ans))
for v in ans:
    print(v)