#pragma region Macros
#include <bits/stdc++.h>
using namespace std;
template <class T> inline bool chmax(T &a, T b) {
    if(a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T> inline bool chmin(T &a, T b) {
    if(a > b) {
        a = b;
        return 1;
    }
    return 0;
}
#ifdef DEBUG
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
    os << '(' << p.first << ',' << p.second << ')';
    return os;
}
template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
    os << '{';
    for(int i = 0; i < (int)v.size(); i++) {
        if(i) { os << ','; }
        os << v[i];
    }
    os << '}';
    return os;
}
void debugg() { cerr << endl; }
template <class T, class... Args>
void debugg(const T &x, const Args &... args) {
    cerr << " " << x;
    debugg(args...);
}
#define debug(...)                                                             \
    cerr << __LINE__ << " [" << #__VA_ARGS__ << "]: ", debugg(__VA_ARGS__)
#define dump(x) cerr << __LINE__ << " " << #x << " = " << (x) << endl
#else
#define debug(...) (void(0))
#define dump(x) (void(0))
#endif

struct Setup {
    Setup() {
        cin.tie(0);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(15);
    }
} __Setup;

using ll = long long;
#define OVERLOAD3(_1, _2, _3, name, ...) name
#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()
#define REP1(i, n) for(int i = 0; i < int(n); i++)
#define REP2(i, a, b) for(int i = (a); i < int(b); i++)
#define REP(...) OVERLOAD3(__VA_ARGS__, REP2, REP1)(__VA_ARGS__)
#define UNIQUE(v) sort(ALL(v)), (v).erase(unique(ALL(v)), (v).end())
#define REVERSE(v) reverse(ALL(v))
#define SZ(v) ((int)(v).size())
const int INF = 1 << 30;
const ll LLINF = 1LL << 60;
constexpr int MOD = 1000000007;
constexpr int MOD2 = 998244353;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

void Case(int i) { cout << "Case #" << i << ": "; }
int popcount(int x) { return __builtin_popcount(x); }
ll popcount(ll x) { return __builtin_popcountll(x); }
#pragma endregion Macros

void solve() {
    int N, K, M, P;
    cin >> N >> K >> M >> P;
    vector<vector<int>> G(N);
    REP(_, M) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        G[u].push_back(v);
        G[v].push_back(u);
    }
    vector<int> s(N), x(K);
    REP(i, N) cin >> s[i];
    REP(i, K) {
        cin >> x[i];
        x[i]--;
    }
    // 0: 未感染, 1: 感染, 2: 免疫獲得, 3: 検疫
    vector<int> state(N, 0);
    using Event = tuple<int, int, int>;
    priority_queue<Event, vector<Event>, greater<Event>> que;
    for(int i : x) {
        state[i] = 1;
        que.emplace(P, 0, i);
        que.emplace(s[i], 1, i);
    }
    while(!que.empty()) {
        auto [d, t, i] = que.top();
        que.pop();
        if(t == 0) {
            if(state[i] == 1) state[i] = 2;
        } else if(state[i] == 1 or state[i] == 2) {
            for(int j : G[i]) {
                if(state[j] >= 2) continue;
                if(state[j] == 0) {
                    state[j] = 1;
                    que.emplace(d + P, 0, j);
                    que.emplace(d + s[j], 1, j);
                } else {
                    assert(state[j] == 1);
                    state[j] = 3;
                }
            }
        }
    }
    int ans = 0;
    REP(i, N) ans += (state[i] == 3);
    cout << ans << endl;
}

int main() {
    int T = 1;
    // cin >> T;
    while(T--) solve();
}