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[] NMi => ReadLine().Split().Select(c => int.Parse(c) - 1).ToArray();
    static int[][] NMap(int n) => Enumerable.Repeat(0, n).Select(_ => NMi).ToArray();
    static int[] LList(long n) => Enumerable.Repeat(0, (int)n).Select(_ => int.Parse(ReadLine())).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, k, m, p) = (c[0], c[1], c[2], c[3]);
        var map = NMap(m);
        var s = LList(n);
        var x = LList(k);
        
        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]].Add(edge[1]);
            tree[edge[1]].Add(edge[0]);
        }

        var q = new PriorityQueue<Pair>(n, false);
        var count = new int[n];
        foreach (var xi in x)
        {
            ++count[xi - 1];
            q.Enqueue(new Pair(xi - 1, 0, p));
            q.Enqueue(new Pair(xi - 1, 1, s[xi - 1]));
            // WriteLine($"day:0, v:{xi - 1}");
        }
        while (q.Count > 0)
        {
            var date = q.List[0].Time;
            var move = new HashSet<int>();
            while (q.Count > 0 && q.List[0].Time == date)
            {
                var cur = q.Dequeue();
                if (cur.Kind == 0 && count[cur.Pos] == 1)
                {
                    // recover
                    count[cur.Pos] = -1;
                    // WriteLine($"day:{date}, recover:{cur.Pos}");
                }
                else if (cur.Kind == 1)
                {
                    // spread
                    if (count[cur.Pos] == 1 || count[cur.Pos] == -1)
                    {
                        foreach (var next in tree[cur.Pos])
                        {
                            if (count[next] == 0)
                            {
                                ++count[next];
                                q.Enqueue(new Pair(next, 0, date + p));
                                q.Enqueue(new Pair(next, 1, date + s[next]));
                                // WriteLine($"day:{date}, v:{next} from {cur.Pos}");
                            }
                            else if (count[next] == 1)
                            {
                                move.Add(next);
                                // WriteLine($"day:{date}, v:{next} from {cur.Pos}, moved");
                            }
                        }
                    }
                }
            }
            foreach (var mi in move) count[mi] = 2;
        }
        WriteLine(count.Count(ci => ci > 1));
    }
    class Pair : IComparable<Pair>
    {
        public int Pos;
        public int Kind;
        public int Time;
        public Pair(int pos, int kind, int time)
        {
            Pos = pos; Kind = kind; Time = time;
        }
        public int CompareTo(Pair b)
        {
            var d = Time.CompareTo(b.Time);
            if (d != 0) return d;
            return Kind.CompareTo(b.Kind);
        }
    }
    class PriorityQueue<T> where T : IComparable<T>
    {
        public T[] List;
        public int Count;
        bool IsTopMax;
        public PriorityQueue(int count, bool isTopMax)
        {
            IsTopMax = isTopMax;
            List = new T[Math.Max(128, count)];
        }
        public void Enqueue(T value)
        {
            if (Count == List.Length)
            {
                var newlist = new T[List.Length * 2];
                for (var i = 0; i < List.Length; ++i) newlist[i] = List[i];
                List = newlist;
            }
            var pos = Count;
            List[pos] = value;
            ++Count;
            while (pos > 0)
            {
                var parent = (pos - 1) / 2;
                if (Calc(List[parent], List[pos], true)) break;
                Swap(parent, pos);
                pos = parent;
            }
        }
        public T Dequeue()
        {
            --Count;
            Swap(0, Count);
            var pos = 0;
            while (true)
            {
                var child = pos * 2 + 1;
                if (child >= Count) break;
                if (child + 1 < Count && Calc(List[child + 1], List[child], false)) ++child;
                if (Calc(List[pos], List[child], true)) break;
                Swap(pos, child);
                pos = child;
            }
            return List[Count];
        }
        bool Calc(T a, T b, bool equalVal)
        {
            var ret = a.CompareTo(b);
            if (ret == 0 && equalVal) return true;
            return IsTopMax ? ret > 0 : ret < 0;
        }
        void Swap(int a, int b)
        {
            var tmp = List[a];
            List[a] = List[b];
            List[b] = tmp;
        }
    }
}