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#include <bits/stdc++.h>
#define int long long
#define pii pair<int, int>
#define piii pair<pair<int,int>, int>
#define st first.first
#define nd first.second
#define rd second
#define For(i, l, r) for (int i = l; i <= r; i++)
#define Forcin(l, r, a)        \
  for (int i = l; i <= r; i++) \
    cin >> a[i];
#define Ford(i, l, r) for (int i = l; i >= r; i--)
#define ben(v) v.begin(), v.end()
#define LOCAL 0
#define LOCAL2 0
using namespace std;
 
const int M = 400005, inf=1e9;
int n,m,k,q, cur_ind, g[M][4], curk;
pii klocki[M], nei[4]={{0, -1}, {1, 0}, {0, 1}, {-1, 0}};
map <pii, int> pola;
bool deleted[M];

void solve(){
    queue <int> q;
    For(i, 1, cur_ind-1){
        auto [x, y]=klocki[i];
        if (x<=0)
            continue;
        For(j, 0, 3){
            int nx=x+nei[j].first, ny=y+nei[j].second;
            g[i][j]=pola[{nx, ny}];
        }
        deleted[i]=0;
        if(g[i][0]==g[i][2]||g[i][1]==g[i][3]){
            q.push(i);
            deleted[i]=1;
        }
    }
    int del=0;
    while(!q.empty()){
        int v=q.front();
        q.pop();
        auto [x, y]=klocki[v];
        del++;
        For(i, 0, 3){
            int nx=x+nei[i].first, ny=y+nei[i].second;
            int j=(i+2)%4, ind=pola[{nx, ny}];
            if (ind>0 && !deleted[ind]){
                g[ind][j]=0;
                if (g[ind][i]==0){
                    q.push(ind);
                    deleted[ind]=1;
                }
            }
        }
    }
    cout << del<<'\n';
}
 
signed main()
{
    cin.tie(0)->sync_with_stdio();
    if (LOCAL)
        freopen("gray/8.in", "r", stdin);
    if (LOCAL2)
        freopen("local_out.txt", "w", stdout);
    cin>>n>>m>>k>>q;
    For(i, 1, k){
        int x, y;
        cin>>x>>y;
        klocki[i]={x, y};
        pola[{x, y}]=i;
    }
    cur_ind=k+1;
    curk=k;
    solve();
    For(i, 1, q){
        int x, y;
        cin>>x>>y;
        int ind=pola[{x, y}];
        if (ind){
            pola.erase({x, y});
            klocki[ind].first=-1;
            curk--;
        }
        else {
            pola[{x, y}]=cur_ind;
            klocki[cur_ind]={x, y};
            curk++;
            cur_ind++;
        }
        solve();
    }
}