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

int main(void) {
    int n,k,m,p;
    cin >> n >> k >> m >> p;
    vector<int> u(m);
    vector<int> v(m);
    vector<vector<int>> g(n);
    for(int i=0;i<m;++i){
        cin >> u[i] >> v[i];
        --u[i];
        --v[i];
        g[u[i]].emplace_back(v[i]);
        g[v[i]].emplace_back(u[i]);
    }
    vector<int> s(n);
    for(int i=0;i<n;++i){
        cin >> s[i];
    }
    vector<int> x(k);
    vector<int> day(n,INT_MAX-1);
    int ans=0;
    priority_queue<tuple<int,int,int>,vector<tuple<int,int,int>>,greater<tuple<int,int,int>>> q;
    for(int i=0;i<k;++i){
        cin >> x[i];
        --x[i];
        day[x[i]]=0;
        q.emplace(p,0,x[i]);
        q.emplace(s[x[i]],1,x[i]);
    }
    while(!q.empty()){
        auto [d,t,h]=q.top();
        q.pop();
        if(t){
            for(auto next: g[h]){
                if(day[next]<INT_MAX-1){
                    day[next]=INT_MAX;
                    ++ans;
                } else if(day[next]<INT_MAX){
                    day[next]=d;
                    q.emplace(d+s[next],1,next);
                    q.emplace(d+p,0,next);
                }
            }
        } else {
            day[h]=INT_MAX;
        }
    }
    cout << ans << endl;
    return 0;
}