/* -*- coding: utf-8 -*-
 *
 * 2431.cc:  No.2431 Viral Hotel - yukicoder
 */

#include<cstdio>
#include<vector>
#include<queue>
#include<algorithm>
 
using namespace std;

/* constant */

const int MAX_N = 100000;

enum { NEG, POS, QRT, IMM };

/* typedef */

typedef vector<int> vi;

struct Event {
  int ev, t, u;
  Event() {}
  Event(int _ev, int _t, int _u): ev(_ev), t(_t), u(_u) {}

  bool operator<(const Event &e) const { return t > e.t; }
};

/* global variables */

vi nbrs[MAX_N];
int ss[MAX_N], xs[MAX_N], sts[MAX_N];

/* subroutines */

/* main */

int main() {
  int n, k, m, p;
  scanf("%d%d%d%d", &n, &k, &m, &p);

  for (int i = 0; i < m; i++) {
    int u, v;
    scanf("%d%d", &u, &v);
    u--, v--;
    nbrs[u].push_back(v);
    nbrs[v].push_back(u);
  }

  for (int i = 0; i < n; i++) scanf("%d", ss + i);
  for (int i = 0; i < k; i++) scanf("%d", xs + i), xs[i]--;

  fill(sts, sts + n, NEG);
  priority_queue<Event> q;
  for (int i = 0; i < k; i++) {
    sts[xs[i]] = POS;
    q.push(Event(POS, ss[xs[i]], xs[i]));
    q.push(Event(IMM, p, xs[i]));
  }

  while (! q.empty()) {
    vi imv, psv;
    int t = q.top().t;
    while (! q.empty() && q.top().t == t) {
      auto e = q.top(); q.pop();
      if (sts[e.u] != QRT) {
	if (e.ev == IMM) imv.push_back(e.u);
	else if (e.ev == POS) psv.push_back(e.u);
      }
    }

    for (auto u: imv)
      sts[u] = IMM;

    for (auto u: psv)
      for (auto v: nbrs[u]) {
	if (sts[v] == NEG) {
	  sts[v] = POS;
	  q.push(Event(POS, t + ss[v], v));
	  q.push(Event(IMM, t + p, v));
	}
	else if (sts[v] == POS) {
	  sts[v] = QRT;
	}
      }
  }

  int cnt = 0;
  for (int u = 0; u < n; u++)
    if (sts[u] == QRT) cnt++;

  printf("%d\n", cnt);
  return 0;
}