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#include <iostream>
#include <set>
#include <queue>
#include <map>
#include <array>
using namespace std;

int calc(set<long long>& points, int n) {
    queue<long long> q;
    set<long long> visited;
    map<long long, array<bool,4>> touched;

    for (long long p : points) {
        bool is_left = p%n==0 || points.find(p-1)==points.end();
        bool is_right = (p+1)%n==0 || points.find(p+1)==points.end();
        bool is_top = points.find(p-n)==points.end();
        bool is_bot = points.find(p+n)==points.end();
        touched.insert({p,{is_left,is_right,is_top,is_bot}});
        if (is_left && is_right) {
            visited.insert(p);
            q.push(p);
        } else if (is_top && is_bot) {
            visited.insert(p);
            q.push(p);
        }
    }

    while (!q.empty()) {
        long long p = q.front();
        q.pop();

        if (p%n!=0 && points.find(p-1)!=points.end() && visited.find(p-1)==visited.end()) {
            touched[p-1][1] = 1;
            if (touched[p-1][0] == 1) {
                visited.insert(p-1);
                q.push(p-1);
            }
        }

        if ((p+1)%n!=0 && points.find(p+1)!=points.end() && visited.find(p+1)==visited.end()) {
            touched[p+1][0] = 1;
            if (touched[p+1][1] == 1) {
                visited.insert(p+1);
                q.push(p+1);
            }
        }

        if (points.find(p-n)!=points.end() && visited.find(p-n)==visited.end()) {
            touched[p-n][3] = 1;
            if (touched[p-n][2] == 1) {
                visited.insert(p-n);
                q.push(p-n);
            }
        }

        if (points.find(p+n)!=points.end() && visited.find(p+n)==visited.end()) {
            touched[p+n][2] = 1;
            if (touched[p+n][3] == 1) {
                visited.insert(p+n);
                q.push(p+n);
            }
        }
    }

    return visited.size();
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int n,m,k,q;
    cin>>n>>m>>k>>q;

    set<long long> points;
    for (int i=0; i<k; i++) {
        int x,y;
        cin>>x>>y;
        points.insert(x-1+(y-1)*n);
    }

    cout<<calc(points,n)<<'\n';

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

        if (points.find(x+y*n) == points.end()) points.insert(x+y*n);
        else points.erase(x+y*n);
        cout<<calc(points,n)<<'\n';
    }

    return 0;
}