#include<bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ll n,k,m,p;
    cin>>n>>k>>m>>p;
    vector<vector<int>> g(n);
    for(int i = 0;i<m;i++){
        int u,v;
        cin>>u>>v;
        u--;v--;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    vector<int> now(n,0);
    vector<int> s(n);
    for(int i = 0;i<n;i++) cin>>s[i];
    using dat = pair<ll,pair<int,int>>;
    priority_queue<dat,vector<dat>,greater<dat>> que;
    for(int i = 0;i<k;i++){
        int x;
        cin>>x;
        x--;
        now[x] = 1;
        que.push(make_pair(s[x],make_pair(1,x)));
        que.push(make_pair(p,make_pair(0,x)));
    }
    int ans = 0;
    while(que.size()){
        auto nown = que.top();
        que.pop();
        ll d = nown.first;
        int t = nown.second.first;
        int ni = nown.second.second;
        if(t==1){
            if(now[ni]<0){
                if(-now[ni]<d) continue;
            }
            for(auto&to:g[ni]){
                if(now[to]==0){
                    now[to] = 1;
                    que.push(make_pair(d+s[to],make_pair(1,to)));
                    que.push(make_pair(d+p,make_pair(0,to)));
                }else if(now[to]==1){
                    now[to] = -d;
                    ans++;
                }
            }
        }else if(t==0){
            if(now[ni]<0) continue;
            now[ni] = 2;
        }
    }
    cout<<ans<<endl;

}