from collections import defaultdict
from graphlib import TopologicalSorter


def main():
    n, m = map(int, input().split())
    a = list(map(int, input().split()))

    adj = defaultdict(list)
    for _ in range(m):
        u, v = map(int, input().split())
        u -= 1
        v -= 1
        if a[u] < a[v]:
            adj[u].append(v)
        if a[v] < a[u]:
            adj[v].append(u)

    _ = int(input())
    b = list(map(lambda x: int(x) - 1, input().split()))
    onoff = [(i in b) for i in range(n)]

    # トポロジカルソート
    ts = TopologicalSorter()
    for i in range(n):
        ts.add(i, *adj[i])

    ans = []
    for i in reversed(list(ts.static_order())):
        if not onoff[i]:  # 消灯しているとき
            continue
        else:  # 点灯しているとき
            ans.append(i + 1)
            for v in adj[i]:
                onoff[v] = not onoff[v]

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


if __name__ == "__main__":
    main()