#include<iostream>
#include<vector>
#include<queue>

using namespace std;

int main( void )
{
    int N, K, M, P;
    cin >> N >> K >> M >> P;

    vector<vector<int>> Graph( N );
    int u, v;
    for( int i = 0; i < M; i++ )
    {
        cin >> u >> v;
        u--, v--;
        Graph[u].push_back( v );
        Graph[v].push_back( u );
    }
    vector<int> S( N );
    for( int i = 0; i < N; i++ )
    {
       cin >> S[i];
    }
    vector<int> invasion_day( N, -1 ), qua_day( N, -1 );
    vector<int> status( N, 0 );
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
    int x;
    for( int i = 0; i < K; i++ )
    {
        cin >> x, x--;
        q.push( make_pair( S[x], x ) );
        invasion_day[x] = 0;
        status[x] = 1;
    }

    pair<int, int> cur;
    int ans = 0;
    while( !q.empty() )
    {
        cur = q.top(), q.pop();
        if( status[cur.second] == 2 && qua_day[cur.second] != cur.first ) continue;
        for( int next : Graph[cur.second] )
        {
            if( status[next] == 2 ) continue;
            if( status[next] == 0 )
            {
                q.push( make_pair( cur.first + S[next], next ) );
                invasion_day[next] = cur.first;
                status[next] = 1;
            }
            else
            {
                if( invasion_day[next] + P > cur.first )
                {
                    ans++;
                    status[next] = 2;
                    qua_day[next] = cur.first;
                }
            }
        }
    }

    cout << ans << endl;

    return 0;
}