#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define all(p) p.begin(),p.end()
#define rep(i,a,b) for(int i=(int)a;i<(int)b;i++)
const int mod=998244353;

int main(){
	int N,K,M,P;
	cin>>N>>K>>M>>P;
	vector<vector<int>> G(N);
	rep(i,0,M){
		int a,b;
		cin>>a>>b;
		a--,b--;
		G[a].push_back(b);
		G[b].push_back(a);
	}
	struct event
	{
		int type;
		int time;
		int ind;
	};
	auto comp_event=[&](event l,event r)->bool{
		if(l.time==r.time) return l.type>r.type;
		return l.time>r.time;
	};
	vector<int> p(N);
	priority_queue<event,vector<event>,std::function<bool(event,event)>> pq(comp_event);
	vector<int> S(N);
	rep(i,0,N) cin>>S[i];
	rep(i,0,K){
		int x;
		cin>>x;
		x--;
		pq.push({1,P,x});
		pq.push({2,S[x],x});
		p[x]++;
	}
	int ans=0;
	while(!pq.empty()){
		auto tmp=pq.top();
		pq.pop();
		//cout<<tmp.type<<" "<<tmp.time<<" "<<tmp.ind+1<<endl;
		if(tmp.type==1){
			p[tmp.ind]=-2;
		}
		if(tmp.type==2){
			if(p[tmp.ind]==-1) continue;
			for(auto x:G[tmp.ind]){
				if(p[x]==-1||p[x]==-2) continue;
				p[x]++;
				if(p[x]==1){
					pq.push({2,tmp.time+S[x],x});
					pq.push({1,tmp.time+P,x});
				}
				if(p[x]==2){
					pq.push({3,tmp.time,x});
				}
			}
		}
		if(tmp.type==3){
			ans++;
			p[tmp.ind]=-1;
		}
	}
	cout<<ans<<"\n";
}