#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;
}