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#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;

unordered_map<ll,int> odw;
bool is[1000'000];
int deg_hor[1000'000];
int deg_ver[1000'000];
int deg_hor2[1000'000];
int deg_ver2[1000'000];
pii poz[1000'000];
int cur = 1;

set<int> left_;

ll n,m;
int k,q;

ll H(pii x)
{
    return (ll)x.ss * (n+3) + x.ff;
} 

void add_vert(int x, int y)
{
    left_.insert(cur);
    poz[cur] = {x,y};
    odw[H({x,y})] = cur;
    is[cur] = 1;
    int l = odw[H({x-1,y})];
    int r = odw[H({x+1,y})];
    int u = odw[H({x,y-1})];
    int d = odw[H({x,y+1})];
    if(l != 0)
    {
        deg_hor[l]++;
        deg_hor[cur]++;
    }
    if(r != 0)
    {
        deg_hor[r]++;
        deg_hor[cur]++;
    }
    if(u != 0)
    {
        deg_ver[u]++;
        deg_ver[cur]++;
    }
    if(d != 0)
    {
        deg_ver[d]++;
        deg_ver[cur]++;
    }
    cur++;
}

void del_vert(int x, int y)
{
    int c = odw[H({x,y})];
    left_.erase(left_.find(c));
    is[c] = 0;
    odw[H({x,y})] = 0;
    int l = odw[H({x-1,y})];
    int r = odw[H({x+1,y})];
    int u = odw[H({x,y-1})];
    int d = odw[H({x,y+1})];
    if(l != 0)
    {
        deg_hor[l]--;
    }
    if(r != 0)
    {
        deg_hor[r]--;
    }
    if(u != 0)
    {
        deg_ver[u]--;
    }
    if(d != 0)
    {
        deg_ver[d]--;
    }
}

int count_del()
{
    int ans = 0;
    queue<int> q;
    forall(i,left_)
    {
        deg_ver2[i] = deg_ver[i];
        deg_hor2[i] = deg_hor[i];
        if((deg_hor2[i] == 0 || deg_ver2[i] == 0) && is[i]) q.push(i);
    }
    while(!q.empty())
    {
        int t = q.front();
        q.pop();
        if(deg_hor2[t] <= -1) continue;
        ans++;
        deg_hor2[t] = -1;
        deg_ver2[t] = -1;
        int x = poz[t].ff;
        int y = poz[t].ss;
      //  cout << x << " " << y << " xy\n";
        int l = odw[H({x-1,y})];
        int r = odw[H({x+1,y})];
        int u = odw[H({x,y-1})];
        int d = odw[H({x,y+1})];
        if(l != 0)
        {
            deg_hor2[l]--;
            if(deg_hor2[l] == 0 || deg_ver2[l] == 0) 
            {
                q.push(l);
                deg_ver2[l] = -1;
            }
        }
        if(r != 0)
        {
            deg_hor2[r]--;
            if(deg_hor2[r] == 0 || deg_ver2[r] == 0)
            {
                q.push(r);
                deg_ver2[r] = -1;
            }
        }
        if(u != 0)
        {
            deg_ver2[u]--;
            if(deg_hor2[u] == 0 || deg_ver2[u] == 0)
            {
                q.push(u);
                deg_ver2[u] = -1;
            }
        }
        if(d != 0)
        {
            deg_ver2[d]--;
            if(deg_hor2[d] == 0 || deg_ver2[d] == 0)
            {
                q.push(d);
                deg_ver2[d] = -1;
            }
        }
    }
    return ans;
}

int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //random_start();
    cin >> n >> m >> k >> q;
    rep(i,k)
    {
        int x,y;
        cin >> x >> y;
        add_vert(x,y);
    }
    cout << count_del() << "\n";
    rep(i,q)
    {
        int x,y;
        cin >> x >> y;
        if(odw[H({x,y})] == 0) add_vert(x,y);
        else del_vert(x,y);
        cout << count_del() << "\n";
    }
}