#include <queue>
#include <iostream>
#include <vector>
#include <cstring>
#include <iostream>
#include <set>
#include <map>
#include <cstring>
//#include <bits/stdc++.h>
using namespace std;

const int maxn = 100005;
vector<int> adj[maxn];
int owner[maxn]; //ke zemam 0 za nicija sopstvenost, 1 za kosta, 2 za kiril
int distArr[maxn];

//plan: treba modificiran bfs za sekoja startna pozicija

int bfs(vector<int> starts, int P) {
    queue<int> q;
    vector<bool> visited(maxn, false);

    for (int s : starts) {
        q.push(s);
        distArr[s] = 0;
        visited[s] = true;
    }

    int cnt = 0;

    while (!q.empty()) {
        int u = q.front();
        q.pop();

        for (int v : adj[u]) {
            if(owner[v] == 2){
                continue;
            }
            if(visited[v]){
                continue;
            }

                visited[v] = true;
                if(owner[v] == 0){
                    owner[v] = 1;
                    cnt++;
                }
                q.push(v);
            }
        }
    

    return cnt;
}

int main() {
    ios::sync_with_stdio(false);

    int n, b1, b2, p;
    cin >> n >> b1 >> b2 >> p;

    vector<int> kosta(b1), kiril(b2);

    for (int i = 0; i < b1; i++){
        cin >> kosta[i];
        owner[kosta[i]] = 1;
    }
    for (int i = 0; i < b2; i++){
        cin >> kiril[i];
        owner[kiril[i]] = 2;
    }

    int m; cin >> m;
    for (int i = 0; i < m; i++){
        int a, b;
        cin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }

    for (int i = 1; i <= n; i++){
        distArr[i] = -1;
    }

    int newCities = bfs(kosta, p);
    cout << min(newCities, p) << endl;

    return 0;
}