Untitled

#include <iostream>
#include <vector>
#include <queue>
using namespace std;
const int maxn = 1e5 + 10;
const int INF = 2e9;
int n, b1, b2, money;
vector<int> graph[maxn];
int main()
{
    ios_base::sync_with_stdio(false);
    vector<bool> visited(n + 1, false);
    queue<int> q;
    cin >> n >> b1 >> b2 >> money;
    int org_money = money;
    for(int i = 0; i < b1; i++) {
        int x;
        cin >> x;
        x--;
        visited[x] = true;
        q.push(x);
    }
    
    for(int i = 0; i < b2; i++) {
        int x;
        cin >> x;
        x--;
        visited[x] = true;
    }
    int m;
    cin >> m;
    for(int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        a--; b--;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }
    while(!q.empty()) {
        int node = q.front();
        q.pop();
        
        for(int i = 0; i < (int) graph[node].size(); i++) {
            int neighbour = graph[node][i];
            if(!visited[neighbour]) {
                visited[neighbour] = true;
                if(money > 0) {
                    money--;
                    q.push(neighbour);
                }
            }
        }
    }
    
    if(money == 0) {
        cout << org_money << endl;
    }
    else {
        cout << org_money - money << endl;
    }
    return 0;
}