#include <bits/stdc++.h>
#include <atcoder/all>
#define SELECTER(_1,_2,_3,SELECT,...) SELECT
#define rep1(i,n) for(int i=0;i<(int)n;++i)
#define rep2(i,a,n) for(int i=(int)a;i<(int)n;++i)
#define rep(...) SELECTER(__VA_ARGS__,rep2,rep1)(__VA_ARGS__)
#define RSELECTER(_1, _2, _3, RSELECT, ...) RSELECT
#define rrep1(i,n) for(int i=(int)n-1;i>=0;--i)
#define rrep2(i,a,n) for(int i=(int)n-1;i>=(int)a;--i)
#define rrep(...) RSELECTER(__VA_ARGS__, rrep2, rrep1)(__VA_ARGS__)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define fi first
#define se second
#define PrintR LogOutput
#ifdef _DEBUG
#define Log(...) LogOutput(__VA_ARGS__)
#else
#define Log(...)
#endif
using namespace std;
using namespace atcoder;
using ll=long long;
using pii=pair<int,int>;
using pll=pair<long long,long long>;
using pdd=pair<long double,long double>;
using veci=vector<int>;
using vecpii=vector<pair<int,int>>;
using vecll=vector<long long>;
using vecpll=vector<pair<long long,long long>>;
using vecpdd=vector<pair<long double,long double>>;
using vecs=vector<string>;
using vecb=vector<bool>;
using vecd=vector<double>;
using tp=tuple<int,int,int>;
using tpll=tuple<ll,ll,ll>;
using mint=modint998244353;
using mint10=modint1000000007;
template<typename T, typename S>
istream& operator>>(istream& in, pair<T, S>& a){return in >> a.first >> a.second;}
template<typename T, typename S>
ostream& operator<<(ostream& out, const pair<T, S>& a){return out << a.first << ' ' << a.second;}
ostream& operator<<(ostream& out, const mint& a){return out << a.val();}
ostream& operator<<(ostream& out, const mint10& a){return out << a.val();}
ostream& operator<<(ostream& out, const modint& a){return out << a.val();}
template<typename T>
ostream& operator<<(ostream& out, const vector<T>& d){for(int i = 0 ; i < d.size() ; ++i) out << d[i] << (i == d.size() - 1 ? "" : " "); return out;}
template<typename T, typename S>
pair<T, S> operator+(const pair<T, S>& a, const pair<T, S>& b){return {a.fi + b.fi, a.se + b.se};}
template<typename T, typename S>
pair<T, S> operator-(const pair<T, S>& a, const pair<T, S>& b){return {a.fi - b.fi, a.se - b.se};}
template<class T> inline bool chmax(T& a,T b){if(a<b) {a=b;return true;} return false;}
template<class T> inline bool chmin(T& a,T b){if(a>b) {a=b;return true;} return false;}
bool Judge(int i, int j, int h, int w){return i < 0 || j < 0 || i >= h || j >= w;}

constexpr ll INF=numeric_limits<ll>::max() / 4;
constexpr ll MOD=998244353;
const int vi[] = {0, 1, 0, -1}, vj[] = {1, 0, -1, 0};

template<typename... Args>
void LogOutput(Args&&... args){
	stringstream ss;
	((ss << args << ' '), ...);
	cout << ss.str().substr(0, ss.str().length() - 1) << endl;
}
template<typename T>
void LogOutput(vector<vector<T>>& data){for(auto d : data) LogOutput(d);}

int main(){
	ios::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int n, k, m, p;cin>>n>>k>>m>>p;
	vector<veci> g(n);
	rep(i, m){
		int a, b;cin>>a>>b;
		a--, b--;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	veci a(n);
	rep(i, n) cin>>a[i];
	veci cnt(n, 0);
	priority_queue<pll, vecpll, greater<pll>> q;
	rep(i, k){
		int b;cin>>b;
		b--;
		q.emplace(p, -b);
		q.emplace(a[b], b + 1);
		cnt[b]++;
	}
	veci res(n, 2);
	int ans = 0;
	veci d;
	while(q.size()){
		auto [b, c] = q.top(); q.pop();
		if(c > 0){
			c--;
			if(res[c]){
				for(int nv : g[c]) if(res[nv] == 2){
					cnt[nv]++;
					if(cnt[nv] == 2){
						d.push_back(nv);
						ans++;
					}else if(cnt[nv] == 1){
						q.emplace(b + p, -nv);
						q.emplace(b + a[nv], nv + 1);
					}
				}
			}
		}else{
			if(res[-c] == 2) res[-c] = 1;
		}
		if(q.size() && b == q.top().fi) continue;
		while(d.size()) res[d.back()] = 0, d.pop_back();
	}
	cout<<ans<<endl;
}