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#include <iostream>
#include <iomanip>
#include <string>
#include <algorithm>
#include <map>
#include <set>
#include <vector>
using namespace std;

//#define DEBUG(x) x
//#define CALC_TIME

#ifndef DEBUG
    #define DEBUG(x)
#endif

#define REP(x,n) for(int x=0;x<(n);++x)
#define VAR(x,n) __typeof(n) x = (n)
#define FOREACH(x,c) for(VAR(x, (c).begin()); x != (c).end(); ++x)
#define CONTAINS(x,elem) ((x).find(elem) != (x).end())

struct Item {
    int x;
    int y;
    bool visible;
    Item *left=nullptr,
        *right=nullptr,
        *top=nullptr,
        *bottom=nullptr;
    int hideOrder=10000000;
    // Item(){}
    // Item(int x, int y, bool visible): x(x), y(y), visible(visible),
    //     left(nullptr), right(nullptr), top(nullptr), bottom(nullptr), hideOrder(-1) {}
};
ostream& operator<<(ostream& os, const Item& item) {
    return os << "[" << item.x<<","<<item.y<<"]/"<<item.visible<<"/"<<item.hideOrder;
}
ostream& operator<<(ostream& os, const Item* item) {
    if (item) {
        return os << *item;
    } else {
        return os << "null";
    }
}

enum Direction {
    HORIZONTAL, VERTICAL, BOTH
};

map<int,map<int,Item>> items;
map<int,set<int>> revIndices;

bool inline hasLeftNeighbour(const Item& item) {
//    DEBUG(cerr<<"hasLeftNeighbour -> "<<item.left<<endl;)
    return item.left != nullptr && item.left->y == item.y-1;
}
bool inline hasRightNeighbour(const Item& item) {
//    DEBUG(cerr<<"hasRightNeighbour -> "<<item.right<<endl;)
    return item.right != nullptr && item.right->y == item.y+1;
}
bool inline hasTopNeighbour(const Item& item) {
//    DEBUG(cerr<<"hasTopRightNeighbour -> "<<item.top<<endl;)
    return item.top != nullptr && item.top->x == item.x-1;
}
bool inline hasBottomNeighbour(const Item& item) {
//    DEBUG(cerr<<"hasBottomNeighbour -> "<<item.bottom<<endl;)
    return item.bottom != nullptr && item.bottom->x == item.x+1;
}

bool inline hasFreeEdges(const Item& item, Direction direction) {
    switch (direction) {
        case HORIZONTAL:
            return (!hasLeftNeighbour(item) || !item.left->visible)
                && (!hasRightNeighbour(item) || !item.right->visible);
        case VERTICAL:
            return (!hasTopNeighbour(item) || !item.top->visible)
                && (!hasBottomNeighbour(item) || !item.bottom->visible);
        case BOTH:
        return (
                (!hasLeftNeighbour(item) || !item.left->visible)
                && (!hasRightNeighbour(item) || !item.right->visible)
            ) || (
                (!hasTopNeighbour(item) || !item.top->visible)
                && (!hasBottomNeighbour(item) || !item.bottom->visible)
            );
    }
    return false;
}

int inline getHideOrderIndex(const Item& item) {
    int horizontalIndex = max(
        hasLeftNeighbour(item) ? item.left->hideOrder + 1 : 0,
        hasRightNeighbour(item) ? item.right->hideOrder + 1 : 0
    );
    int verticalIndex = max(
        hasBottomNeighbour(item) ? item.bottom->hideOrder + 1 : 0,
        hasTopNeighbour(item) ? item.top->hideOrder + 1 : 0
    );
    return min(horizontalIndex, verticalIndex);
}

void restoreWithChildren(Item& root, vector<Item*>& result) {
    if (root.visible) {
        return;
    }
    DEBUG(cerr<<"restoring "<<root<<endl;)
    result.push_back(&root);
    root.visible = true;
    DEBUG(cerr<<" check restore left "<<root.left<<endl;)
    if (root.left && root.left->hideOrder > root.hideOrder)
        restoreWithChildren(*root.left, result);
    DEBUG(cerr<<" check restore right "<<root.right<<endl;)
    if (root.right && root.right->hideOrder > root.hideOrder)
        restoreWithChildren(*root.right, result);
    DEBUG(cerr<<" check restore top "<<root.top<<endl;)
    if (root.top && root.top->hideOrder > root.hideOrder)
        restoreWithChildren(*root.top, result);
    DEBUG(cerr<<" check restore bottom "<<root.bottom<<endl;)
    if (root.bottom && root.bottom->hideOrder > root.hideOrder)
        restoreWithChildren(*root.bottom, result);
    root.hideOrder = 10000000;
}

vector<Item*> restoreVisibility(const Item& root) {
    vector<Item*> result;
    if (root.left)
        restoreWithChildren(*root.left, result);
    if (root.right)
        restoreWithChildren(*root.right, result);
    if (root.top)
        restoreWithChildren(*root.top, result);
    if (root.bottom)
        restoreWithChildren(*root.bottom, result);
    return result;
}

void calcNeighbourhood() {
    for (auto& row : items) {
        Item* previous = nullptr;
        for(auto& item : row.second) {
            if(previous) {
                item.second.left = previous;
                previous->right = &item.second;
            }
            auto& column = revIndices[item.second.y];
            auto findItemInColumn = column.find(item.second.x);
            if (findItemInColumn != column.begin()) {
                item.second.top = &items[*prev(findItemInColumn)][item.second.y];
                item.second.top->bottom = &item.second;
            }

            previous = &item.second;
        }
    }
}

int tryRecursiveHide(Item& item);

int doHide(Item& item, Direction direction) {
    item.hideOrder = item.visible ? getHideOrderIndex(item) : item.hideOrder;
    DEBUG(
        cerr << "hide brick "<<item<<" - "<<direction<<endl;
        cerr << "  left: "<<item.left<<endl;
        cerr << "  right: "<<item.right<<endl;
        cerr << "  top: "<<item.top<<endl;
        cerr << "  bottom: "<<item.bottom<<endl;
    )
    item.visible = false;
    int result = 0;
    switch (direction) {
        case HORIZONTAL:
            if (item.top)
                result += tryRecursiveHide(*item.top);
            if (item.bottom)
                result += tryRecursiveHide(*item.bottom);
            break;
        case VERTICAL:
            if (item.left)
                result += tryRecursiveHide(*item.left);
            if (item.right)
                result += tryRecursiveHide(*item.right);
            break;
        case BOTH:
            if (item.top)
                result += tryRecursiveHide(*item.top);
            if (item.bottom)
                result += tryRecursiveHide(*item.bottom);
            if (item.left)
                result += tryRecursiveHide(*item.left);
            if (item.right)
                result += tryRecursiveHide(*item.right);
            break;
    }
    return result;
}

int tryRecursiveHide(Item& item) {
    if (!item.visible)
        return 0;
    //DEBUG(cerr << "try recursive hide ["<<item.x<<","<<item.y<<"]"<<endl;)
    if (hasFreeEdges(item, HORIZONTAL)) {
        return 1 + doHide(item, HORIZONTAL);
    } else if (hasFreeEdges(item, VERTICAL)) {
        return 1 + doHide(item, VERTICAL);
    } else {
        return 0;
    }
}

int hideAllAndCount() {
    DEBUG(
        for (int i=1;i<=5;++i) {
            for (int j=1;j<=5;++j) {
                if (CONTAINS(items, i) && CONTAINS(items[i], j))
                    cerr << "X";
                else
                    cerr << " ";
            }
            cerr << endl;
        }
    );
    int result = 0;
    for (auto& row : items) {
        for (auto& item : row.second) {
            result += tryRecursiveHide(item.second);
        }
    }
    return result;
}

int hideAndCount(const vector<Item*>& itemsToRecalculate) {
    DEBUG(
        for (int i=1;i<=5;++i) {
            for (int j=1;j<=5;++j) {
                if (CONTAINS(items, i) && CONTAINS(items[i], j))
                    cerr << "X";
                else
                    cerr << " ";
            }
            cerr << endl;
        }
    );
    int result = 0;
    for(auto itemPtr : itemsToRecalculate) {
        result += tryRecursiveHide(*itemPtr);
    }
    return result;
}

int recalcNeighbours(Item& item) {
    return doHide(item, BOTH);
}

void solve() {
    int n,m,k,q;
    cin>>n>>m>>k>>q;
    int x,y;
    REP(i,k) {
        cin>>x>>y;
        items[x][y] = {x, y, true};
        revIndices[y].insert(x);
    }
    calcNeighbourhood();
    int currentResult = hideAllAndCount();
    cout << currentResult << endl;

    
    REP(i,q) {
        cin>>x>>y;
        if (CONTAINS(items, x) && CONTAINS(items[x], y)) {
            Item& itemToRemove = items[x][y];
            if (itemToRemove.visible) {
                DEBUG(cerr << "remove visible " << x << "," << y << endl;)
                itemToRemove.visible = false;
                itemToRemove.hideOrder = 0;
                currentResult += recalcNeighbours(itemToRemove);
            } else {
                DEBUG(cerr << "remove invisible " << x << "," << y << endl;)
                --currentResult;
            }
            if (itemToRemove.left)
                itemToRemove.left->right = itemToRemove.right;
            if (itemToRemove.right)
                itemToRemove.right->left = itemToRemove.left;
            if (itemToRemove.top)
                itemToRemove.top->bottom = itemToRemove.bottom;
            if (itemToRemove.bottom)
                itemToRemove.bottom->top = itemToRemove.top;

            DEBUG(
                cerr << "remove brick "<<itemToRemove<<endl;
                cerr << "  left: "<<itemToRemove.left<<endl;
                cerr << "  right: "<<itemToRemove.right<<endl;
                cerr << "  top: "<<itemToRemove.top<<endl;
                cerr << "  bottom: "<<itemToRemove.bottom<<endl;
            )
            items[x].erase(y);
            revIndices[y].erase(x);
        } else {            
            DEBUG(cerr << "add new " << x << "," << y << endl;)
            Item& newItem = items[x][y] = {x, y, true};
            auto& column = revIndices[y];
            column.insert(x);
            auto findRow = items.find(x);
            auto findItem = findRow->second.find(y);
            if (findItem != findRow->second.begin()) {
                newItem.left = &prev(findItem)->second;
                newItem.right = newItem.left->right;
                newItem.left->right = &newItem;
                if (newItem.right)
                    newItem.right->left = &newItem;
                DEBUG(cerr << "setting left and right based on left" << newItem.left << ", " << newItem.right << endl;)
            } else if (next(findItem) != findRow->second.end()) {
                newItem.right = &next(findItem)->second;
                newItem.right->left = &newItem;
                // no need to set newItem.left, since we already know there's nothing there
                DEBUG(cerr << "setting left and right based on right" << newItem.left << ", " << newItem.right << endl;)
            } else {
                DEBUG(cerr << "not setting left and right - all empty" << endl;)
            }
            auto columnIter = column.find(x);
            if (columnIter != column.begin()) {
                newItem.top = &items[*prev(columnIter)][y];
                newItem.bottom = newItem.top->bottom;
                newItem.top->bottom = &newItem;
                if (newItem.bottom)
                    newItem.bottom->top = &newItem;
                DEBUG(cerr << "setting top and bottom based on top" << newItem.top << ", " << newItem.bottom << endl;)
            } else if (next(columnIter) != column.end()) {
                newItem.bottom = &items[*next(columnIter)][y];
                newItem.bottom->top = &newItem;
                // no need to set newItem.top since we already know there's nothing there
                DEBUG(cerr << "setting top and bottom based on bottom" << newItem.top << ", " << newItem.bottom << endl;)
            } else {
                DEBUG(cerr << "not setting top and bottom - all empty" << endl;)
            }
            vector<Item*> affectedItems = restoreVisibility(newItem);
            currentResult -= affectedItems.size();
            DEBUG(cerr<<"restored "<<affectedItems.size()<<" items"<<endl;)
            affectedItems.push_back(&newItem);
            currentResult += hideAndCount(affectedItems);
        }
        cout << currentResult << endl;
    }
}

#ifdef CALC_TIME
#include <ctime>
#endif

int main() {
    ios_base::sync_with_stdio(0);

#ifdef CALC_TIME
    clock_t begin = clock();
#endif

    solve();

#ifdef CALC_TIME
    cerr << "TIME: " << float(clock()-begin)/CLOCKS_PER_SEC << " s " << endl;
#endif
}