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#include <bits/stdc++.h>
using namespace std;

set<pair<int, int>> klocki;

map<pair<int, int>, pair<pair<bool, bool>, pair<bool, bool>>> usun; // ((x + 1, y) (x - 1, y)) ((x, y + 1), (x, y - 1))

void fill(queue<pair<int, int>>& q) {
    // cerr << "start:\n";
    for (auto k: klocki) {
        int x = k.first, y = k.second;
        usun[k] = {{klocki.find({x + 1, y}) == klocki.end(), klocki.find({x - 1, y}) == klocki.end()}, {klocki.find({x, y + 1}) == klocki.end(), klocki.find({x, y - 1}) == klocki.end()}};
        if (usun[k].first == make_pair(true, true) || usun[k].second == make_pair(true, true)) {
            q.push(k);
            // cerr << "wrzucam " << k.first << " " << k.second << "\n";
        }
    }    
}

int bfs(queue<pair<int, int>>& q) {
    int ile = 0;
    while (!q.empty()) {
    // {
        pair<int, int> k = q.front();
        // cerr << "przetwarzam " << k.first << " " << k.second << "\n";
        int x = k.first, y = k.second;
        q.pop();
        ile++;

        if (klocki.find({x - 1, y}) != klocki.end()) {
            usun[{x - 1, y}].first.first = 1;
            if (usun[{x - 1, y}].first == make_pair(true, true) && usun[{x - 1, y}].second != make_pair(true, true)) {
                q.push({x - 1, y});
                // cerr << "wrzucam " << x - 1 << " " << y << "\n";
            }            
        }
        if (klocki.find({x + 1, y}) != klocki.end()) {
            usun[{x + 1, y}].first.second = 1;
            if (usun[{x + 1, y}].first == make_pair(true, true) && usun[{x + 1, y}].second != make_pair(true, true)) {
                q.push({x + 1, y});
                // cerr << "wrzucam " << x + 1 << " " << y << "\n";
            }            
        }
        if (klocki.find({x, y - 1}) != klocki.end()) {
            usun[{x, y - 1}].second.first = 1;
            if (usun[{x, y - 1}].second == make_pair(true, true) && usun[{x, y - 1}].first != make_pair(true, true)) {
                q.push({x, y - 1});
                // cerr << "wrzucam " << x << " " << y - 1 << "\n";
            }            
        }
        if (klocki.find({x, y + 1}) != klocki.end()) {
            usun[{x, y + 1}].second.second = 1;
            if (usun[{x, y + 1}].second == make_pair(true, true) && usun[{x, y + 1}].first != make_pair(true, true)) {
                q.push({x, y + 1});
                // cerr << "wrzucam " << x << " " << y + 1 << "\n";
            }            
        }
    }

    return ile;
}

int check() {
    queue<pair<int, int>> q;
    fill(q);

    return bfs(q);
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    
    int n, m, k, q;
    cin >> n >> m >> k >> q;

    for (int i = 0; i < k; i++) {
        int x, y;
        cin >> x >> y;
        klocki.insert({x, y});
    }

    int out = check();
    cout << out << "\n";

    for (int i = 0; i < q; i++) {
        int x, y;
        cin >> x >> y;

        auto it = klocki.find({x, y});
        if (it != klocki.end()) {
            klocki.erase(it);

            // jeśli usuwam coś, co i tak byłoby usunięte
            if (usun[{x, y}].first == make_pair(true, true) || usun[{x, y}].second == make_pair(true, true)) {
                out--;
            }
            else {
                queue<pair<int, int>> queue;
                queue.push({x, y});
                out += bfs(queue) - 1;
            }
        }
        else {
            klocki.insert({x, y});
            usun[{x, y}] = {{klocki.find({x + 1, y}) == klocki.end(), klocki.find({x - 1, y}) == klocki.end()}, {klocki.find({x, y + 1}) == klocki.end(), klocki.find({x, y - 1}) == klocki.end()}};
            if (usun[{x, y}].first == make_pair(true, true) || usun[{x, y}].second == make_pair(true, true)) {
                out++;
            }
            else {
                out = check();
            }
            
        }

        cout << out << "\n";
    }
}