#include <bits/stdc++.h>
using namespace std;
#define FOR(i,m,n) for(int i=(m);i<(n);++i)
#define REP(i,n) FOR(i,0,n)
using ll = long long;
constexpr int INF = 0x3f3f3f3f;
constexpr long long LINF = 0x3f3f3f3f3f3f3f3fLL;
constexpr double EPS = 1e-8;
constexpr int MOD = 998244353;
// constexpr int MOD = 1000000007;
constexpr int DY4[]{1, 0, -1, 0}, DX4[]{0, -1, 0, 1};
constexpr int DY8[]{1, 1, 0, -1, -1, -1, 0, 1};
constexpr int DX8[]{0, -1, -1, -1, 0, 1, 1, 1};
template <typename T, typename U>
inline bool chmax(T& a, U b) { return a < b ? (a = b, true) : false; }
template <typename T, typename U>
inline bool chmin(T& a, U b) { return a > b ? (a = b, true) : false; }
struct IOSetup {
  IOSetup() {
    std::cin.tie(nullptr);
    std::ios_base::sync_with_stdio(false);
    std::cout << fixed << setprecision(20);
  }
} iosetup;

int main() {
  int n, k, m, p; cin >> n >> k >> m >> p;
  vector<vector<int>> graph(n);
  while (m--) {
    int u, v; cin >> u >> v; --u; --v;
    graph[u].emplace_back(v);
    graph[v].emplace_back(u);
  }
  vector<int> s(n); REP(i, n) cin >> s[i];
  vector<int> infected(n, 0);
  set<tuple<int, bool, int>> days;  // day, recover/spread, room
  while (k--) {
    int x; cin >> x; --x;
    infected[x] = 1;
    days.emplace(p, false, x);
    days.emplace(s[x], true, x);
  }
  while (!days.empty()) {
    const auto [d, type, room] = *days.begin();
    days.erase(days.begin());
    if (infected[room] == -1) continue;
    if (type) {
      for (const int e : graph[room]) {
        if (infected[e] > 0) {
          infected[e] = -1;
        } else if (infected[e] == 0) {
          infected[e] = 1;
          days.emplace(d + p, false, e);
          days.emplace(d + s[e], true, e);
        }
      }
    } else {
      infected[room] = -2;
    }
    // cout << d << ' ' << type << ' ' << room << '\n';
    // REP(i, n) cout << infected[i] << " \n"[i + 1 == n];
  }
  cout << ranges::count(infected, -1) << '\n';
  return 0;
}