package main

import . "fmt"
import . "os"
import bf "bufio"
import . "sort"

type T struct { id, value int }

func main() {
	rd := bf.NewReader(Stdin)
	wr := bf.NewWriter(Stdout)
	defer wr.Flush()
	
	var n,m int
	Fscan(rd,&n,&m)
	
	a := make([]int, n)
	for i := range a {
		Fscan(rd, &a[i])
	}
	
	graph := make([][]int, n)
	for i := 0; i < m; i++ {
		var u,v int
		Fscan(rd,&u,&v)
		u--
		v--
		if a[u] < a[v] {
			graph[u] = append(graph[u], v)
		}
		if a[u] > a[v] {
			graph[v] = append(graph[v], u)
		}
	}
	
	light := make([]bool, n)
	
	var k int
	Fscan(rd, &k)
	for i := 0; i < k; i++ {
		var b int
		Fscan(rd,&b)
		light[b-1] = true
	}
	
	ts := make([]*T, n)
	for i := range ts {
		ts[i] = &T{ 
			id: i, 
			value: a[i],
		}
	}
	Slice(ts, func(i, j int) bool {
		return ts[i].value < ts[j].value
	})

	ans := []int{}
	for _, t := range ts {
		if !light[t.id] {
			continue
		}
		ans = append(ans, t.id)
		for _, e := range graph[t.id] {
			light[e] = !light[e]
		}
	}
	
	Println(len(ans))
	for _, id := range ans {
		Println(id+1)
	}
}

/*
考察

因果的に
A[i]の小さい順に消灯していくだけだと思われる

グラフはA[u]<A[v]の方向の有向辺の有向グラフを構築しとくといいのかも


*/