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

#define ll long long

bool czy (int x, int y, map<pair<int, int>, bool> &mp) {
    if ((!mp[{x-1, y}] && !mp[{x+1, y}]) || (!mp[{x, y-1}] && !mp[{x, y+1}])) {
        return 1;
    }
    return 0;
}

void licz (map<pair<int, int>, bool> mp) {
    queue<pair<int, int>> q;
    int l = 0;
    for (auto i : mp) {
        if (i.second) {
            if (czy(i.first.first, i.first.second, mp)) {
                q.push({i.first.first, i.first.second});
            }
        }
    }
    while (!q.empty()) {
        auto x = q.front();
        q.pop();
        if (!mp[{x.first, x.second}]) {
            continue;
        }
        l++;
        mp[{x.first, x.second}] = 0;
        if (mp[{x.first-1, x.second}] && czy(x.first-1, x.second, mp)) {
            q.push({x.first-1, x.second});
        }
        if (mp[{x.first+1, x.second}] && czy(x.first+1, x.second, mp)) {
            q.push({x.first+1, x.second});
        }
        if (mp[{x.first, x.second-1}] && czy(x.first, x.second-1, mp)) {
            q.push({x.first, x.second-1});
        }
        if (mp[{x.first, x.second+1}] && czy(x.first, x.second+1, mp)) {
            q.push({x.first, x.second+1});
        }
    }
    cout << l << '\n';
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m, k, q;
    cin >> n >> m >> k >> q;
    vector<pair<int, int>> w;
    map<pair<int, int>, bool> mp;
    for (int i = 0; i < k; i++) {
        int x, y;
        cin >> x >> y;
        w.push_back({x, y});
        mp[{x, y}] = 1;
    }
    licz(mp);
    for (int i = 0; i < q; i++) {
        int x, y;
        cin >> x >> y;
        mp[{x, y}] = !mp[{x, y}];
        licz(mp);
    }
}