#include "bits/stdc++.h"
#include <unordered_map>
#include <unordered_set>

#include <stdio.h>
#include <math.h>
#include <cassert>

#pragma warning(push)
#pragma warning(disable:26498 26450 26451 26812)
#include "atcoder/all"
#pragma warning(pop)

#include <float.h>


//#include <boost/multiprecision/cpp_int.hpp>
//using namespace boost::multiprecision;
// std::fixed << std::setprecision(10) <<

using namespace std;
using namespace atcoder;

using ll = long long;
using ull = unsigned long long;
using mint = modint998244353;
using mint2 = modint1000000007;

const double eps = 1e-9;

#define REP(i, n) for (ll i = 0; i < ll(n); ++i)
#define REPI(i, init, n) for (ll i = init; i < ll(n); ++i)
#define REPD(i, init) for (ll i = init; i >=0; --i)
#define REPDI(i, init, n) for (ll i = init; i >=n; --i)
#define REPE(i, c) for (const auto& i : c)

using vl = vector<ll>;
#define VL(a, n) vector<ll> a; a.assign(n, 0);
#define VLI(a, n) vector<ll> a; a.assign(n, 0); for(auto& x : a) cin >> x;
#define VSI(a, n) vector<string> a; a.assign(n, ""); for(auto& x : a) cin >> x;
using vvl = vector<vector<ll>>;
#define VVLI(a, n, m, init) vector<vector<ll>> a(n); for(auto& x : a) x.assign(m, init);
using pl = pair<ll, ll>;

struct uv { ll u; ll v; ll c; };
#define VUVI(a, n) vector<uv> a; a.assign(n, {0, 0, 1}); for(auto& x : a) {cin >> x.u >> x.v; x.u--; x.v--;}
#define VUVCI(a, n) vector<uv> a; a.assign(n, {0, 0, 0}); for(auto& x : a) {cin >> x.u >> x.v >> x.c; x.u--; x.v--;}
vvl to_edge(const ll n, const vector<uv>& v) { vvl ret(n); for (auto& x : v) ret[x.u].push_back(x.v); return ret; }
vvl to_edge_d(const ll n, const vector<uv>& v) { vvl ret(n); for (auto& x : v) { ret[x.u].push_back(x.v); ret[x.v].push_back(x.u); } return ret; }

template <class T = long long> using pql = priority_queue<T>;
template <class T = long long> using pqg = priority_queue<T, vector<T>, greater<T>>;
using vm = vector<mint>;
using vvm = vector<vm>;

const char* YES = "Yes";
const char* NO = "No";
void yn(bool f) { std::cout << (f ? YES : NO) << endl; };
template<class T> void ov(const T& v) { for (auto it = v.begin(); it != v.end(); it++) { if (it != v.begin()) cout << " "; cout << *it; } };
template<> void ov(const vm& v) { for (auto it = v.begin(); it != v.end(); it++) { if (it != v.begin()) cout << " "; cout << it->val(); } };

const ll llhuge = 1LL << 60; //十分でかいが多少足しても溢れない数値
template<class T, class U> bool chmin(T& a, const U& b) { a = min(a, b); return b == a; }
template<class T, class U> bool chmax(T& a, const U& b) { a = max(a, b); return b == a; }
template<class T> void mysort(T& v) { std::sort(begin(v), end(v)); };
template<class T, class U> void mysort(T& v, U pr) { std::sort(begin(v), end(v), pr); };
template<class T> void myrev(T& v) { std::reverse(begin(v), end(v)); };


int main() {
	cin.tie(nullptr);
	ios::sync_with_stdio(false);

	ll n, k, m, p;
	cin >> n >> k >> m >> p;

	VUVI(uv, m);
	auto g = to_edge_d(n, uv);

	vl st(n, 0); //0未感染 1感染 2免疫 3不在
	VLI(s, n);

	pqg<pair<ll, pair<ll, ll>>> q;

	REP(i, k) {
		ll x;
		cin >> x;
		x--;
		st[x] = 1;
		q.push({ s[x], {2, x} }); //感染イベント
		q.push({ p, {1, x} }); //回復イベント
	}

	ll ans = 0;
	while (!q.empty()) {
		auto t = q.top();
		q.pop();
		ll now = t.first;

		if (t.second.first == 1) {
			//回復
			if (st[t.second.second] == 1) {
				st[t.second.second] = 2;
			}
		}
		if (t.second.first == 2 && st[t.second.second] < 3) {
			//感染
			REPE(e, g[t.second.second]) {
				if (st[e] == 0) {
					st[e] = 1;
					q.push({ now + s[e], {2, e} }); //感染イベント
					q.push({ now + p, {1, e} }); //回復イベント
				}
				else if (st[e] == 1) {
					st[e] = 3;
					ans++;
				}
			}
		}
	}

	cout << ans << endl;

	return 0;
}