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#include <cstdio>
#include <set>
#include <vector>
#include <map>
#include <queue>

#define DEBUG false

using namespace std;


int comp_iteration = 0;
int total_zdejmovables = 0;
queue<int> klocklejka;

struct klocek {
    int id;
    int neighbors[4]; // up - down - left - right
    int zdejmovability; // up + 2down + 4left + 8right
    int iteration_seen;
    int iteration_visited;
    bool removed;
};

bool zdejmovable(int zity) {
    int updown = zity % 4;
    int leftright = zity % 16;
    return updown == 0 || leftright < 4;
}

vector<klocek> klockis;
map<pair<int, int>, int> klockids;

int get_klocek_id(int x, int y) {
    if (x < 0) return -1;
    if (y < 0) return -1;
    auto val = klockids.find(make_pair(x, y));
    if (val == klockids.end()) return -1;
    return val->second;
}

void renew_zdejmovability(int klocek_id) {
    if constexpr (DEBUG) printf("Renewing %d\n", klocek_id);
    int zdejm = 0;
    if (klockis[klocek_id].neighbors[0] != -1) {
        if constexpr (DEBUG) printf("Has up neb\n");
        zdejm += 1;
    }
    if (klockis[klocek_id].neighbors[1] != -1) {
        if constexpr (DEBUG) printf("Has down neb\n");
        zdejm += 2;
    }
    if (klockis[klocek_id].neighbors[2] != -1) {
        if constexpr (DEBUG) printf("Has left neb\n");
        zdejm += 4;
    }
    if (klockis[klocek_id].neighbors[3] != -1) {
        if constexpr (DEBUG) printf("Has right neb\n");
        zdejm += 8;
    }
    klockis[klocek_id].zdejmovability = zdejm;
    if constexpr (DEBUG) printf("Renewed to %d zity\n", zdejm);
}

void compute_zdejmovables() {
    while (!klocklejka.empty()) {
        int klocek_id = klocklejka.front();
        klocklejka.pop();
        if constexpr (DEBUG) printf("Checking %d (current_zity: %2d, last_visited: %2d))\n", klocek_id, klockis[klocek_id].zdejmovability, klockis[klocek_id].iteration_visited);
        if (zdejmovable(klockis[klocek_id].zdejmovability) && klockis[klocek_id].iteration_visited < comp_iteration) {
            if constexpr (DEBUG) printf("Zdejming %d!\n", klocek_id);
            klockis[klocek_id].iteration_visited = comp_iteration;
            for (int i = 0; i < 4; ++i) {
                int nid = klockis[klocek_id].neighbors[i];
                if (nid != 1) {
                    if constexpr (DEBUG) printf("Processing neighbor of %d : %d\n", klocek_id, nid);
                    if (klockis[nid].iteration_seen < comp_iteration) {
                        klockis[nid].iteration_seen = comp_iteration;
                        renew_zdejmovability(nid);
                    }
                    int zity_minus = 0;
                    switch (i) {
                        case 0: zity_minus = 2; break;
                        case 1: zity_minus = 1; break;
                        case 2: zity_minus = 8; break;
                        case 3: zity_minus = 4; break;
                    }
                    klockis[nid].zdejmovability -= zity_minus;
                }
            }
            total_zdejmovables += 1;
            for (int i = 0; i < 4; ++i) {
                int nid = klockis[klocek_id].neighbors[i];
                if (nid != -1) klocklejka.push(nid);
            }
        }
    }
}

void start_compute_zdejmovables() {
    // compute ab ovo, based only on klocek placements
    klocklejka = queue<int>();
    total_zdejmovables = 0;

    if constexpr (DEBUG) printf("======================================\n");
    if constexpr (DEBUG) printf("ITERATION %d\n", comp_iteration);

    for (int i = 0; i < klockis.size(); ++i) {
        if (klockis[i].removed) continue;
        if (klockis[i].iteration_seen < comp_iteration) {
            klockis[i].iteration_seen = comp_iteration;
            renew_zdejmovability(i);
        }
        klocklejka.push(i);
        compute_zdejmovables();
    }

    printf("%d\n", total_zdejmovables);
}

// przerabiamy na graf, wstawienie/usunięcie klocka dodaje/usuwa krawędzie (max 4)
// przechodzimy DFSem po tym grafie żeby policzyć zdejmovability

int main() {
    int n, m, k, q;
    scanf("%d %d %d %d", &n, &m, &k, &q);

    int klocek_id = 0;
    for (int i = 0; i < k; ++i) {
        int x, y;
        scanf("%d %d", &x, &y);
        klockids[make_pair(x, y)] = klocek_id;

        int upneigh = get_klocek_id(x, y-1);
        int downeigh = get_klocek_id(x, y+1);
        int leftneigh = get_klocek_id(x-1, y);
        int rightneigh = get_klocek_id(x+1, y);

        klockis.push_back(klocek{klocek_id, {upneigh, downeigh, leftneigh, rightneigh}, 0, -1, -1, false});
        if constexpr (DEBUG) printf("Creating klocek %d, neighbor ids: %d | %d | %d | %d\n", klocek_id, upneigh, downeigh, leftneigh, rightneigh);
        if (upneigh != -1) {
            klockis[upneigh].neighbors[1] = klocek_id;
        }
        if (downeigh != -1) {
            klockis[downeigh].neighbors[0] = klocek_id;
        }
        if (leftneigh != -1) {
            klockis[leftneigh].neighbors[3] = klocek_id;
        }
        if (rightneigh != -1) {
            klockis[rightneigh].neighbors[2] = klocek_id;
        }
        klocek_id += 1;
    }

    start_compute_zdejmovables();

    for (int i = 0; i < q; ++i) {
        comp_iteration++;
        int x, y;
        scanf("%d %d", &x, &y);
        int id = get_klocek_id(x, y);

        int upneigh = get_klocek_id(x, y-1);
        int downeigh = get_klocek_id(x, y+1);
        int leftneigh = get_klocek_id(x-1, y);
        int rightneigh = get_klocek_id(x+1, y);

        if (id == -1) {
            // add klocek
            klockis.push_back(klocek{klocek_id, {upneigh, downeigh, leftneigh, rightneigh}, 0, -1, -1, false});
            if (upneigh != -1) {
                klockis[upneigh].neighbors[1] = klocek_id;
            }
            if (downeigh != -1) {
                klockis[downeigh].neighbors[0] = klocek_id;
            }
            if (leftneigh != -1) {
                klockis[leftneigh].neighbors[3] = klocek_id;
            }
            if (rightneigh != -1) {
                klockis[rightneigh].neighbors[2] = klocek_id;
            }
        } else {
            // remove klocek
            klockis[id].removed = true;
            if (upneigh != -1) {
                klockis[upneigh].neighbors[1] = -1;
            }
            if (downeigh != -1) {
                klockis[downeigh].neighbors[0] = -1;
            }
            if (leftneigh != -1) {
                klockis[leftneigh].neighbors[3] = -1;
            }
            if (rightneigh != -1) {
                klockis[rightneigh].neighbors[2] = -1;
            }
        }
        start_compute_zdejmovables();
    }
    return 0;
}