using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, m) = (c[0], c[1]);
        var a = NList;
        var map = NArr(m);
        var k = NN;
        var b = NList;

        var vlist = new (int id, int a)[n];
        for (var i = 0; i < n; ++i) vlist[i] = (i, a[i]);
        Array.Sort(vlist, (l, r) => l.a.CompareTo(r.a));
        var tree = new List<int>[n];
        for (var i = 0; i < tree.Length; ++i) tree[i] = new List<int>();
        foreach (var edge in map)
        {
            tree[edge[0] - 1].Add(edge[1] - 1);
            tree[edge[1] - 1].Add(edge[0] - 1);
        }
        var lamp = new bool[n];
        foreach (var bi in b) lamp[bi - 1] = true;
        var ans = new List<int>();
        foreach (var v in vlist)
        {
            if (lamp[v.id])
            {
                ans.Add(v.id);
                lamp[v.id] = false;
                foreach (var next in tree[v.id]) if (a[v.id] < a[next])
                {
                    lamp[next] = !lamp[next];
                }
            }
        }
        WriteLine(ans.Count);
        WriteLine(string.Join("\n", ans.Select(ai => ai + 1)));
    }
}