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#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb push_back
#define pii pair<int,int>
#define pl pair<ll,ll>
#define F first
#define S second
#define pq priority_queue
#define all(x) x.begin(), x.end()
#define deb(x) cout << #x << " = " << x << '\n';
#define deb2(x,y) cout << #x << " = " << x << ", " << #y << " = " << y << '\n';

constexpr int M = 1e9+7;
constexpr int N = 1e6+7;
constexpr bool debug = 0;

map<pii,int> takable;
vector<pii> rw = {{0,1},{1,0},{0,-1},{-1,0}};
set<pii> vtx;
int n, m, kok, q;

void proc(){
	int sc = 0;
	queue<pii> todo;
	for(auto k: vtx){
		takable[k] = -1;
		int ver = 0, hor = 0;
		if(takable[{k.F,k.S+1}] || takable[{k.F,k.S-1}]) ver++;
		if(takable[{k.F+1,k.S}] || takable[{k.F-1,k.S}]) hor++;

		if(ver == 0 || hor == 0){
			takable[k] = 1;
			todo.push(k);
		}
	}

	while(!todo.empty()){
		sc++;
		pii ob = todo.front();
		todo.pop();
		for(auto k: rw){
			pii totak = {ob.F+k.F, ob.S+k.S};
			if(takable[totak] == 0 || takable[totak] == 1) continue;
			int ver = 0, hor = 0;
			if(takable[{totak.F,totak.S+1}] == -1 || takable[{totak.F,totak.S-1}] == -1) ver++;
			if(takable[{totak.F+1,totak.S}] == -1 || takable[{totak.F-1,totak.S}] == -1) hor++;

			if(ver == 0 || hor == 0){
				takable[totak] = 1;
				todo.push(totak);
			}
		}
	}
	cout << sc << '\n';
}

int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	 cin >> n >> m >> kok >> q;
	for(int i = 0; i < kok; i++){
		pii a; cin >> a.F >> a.S;
		vtx.insert(a);
		takable[a] = -1;
	}
	proc();
	while(q--){
		pii ok; cin >> ok.F >> ok.S;
		if(vtx.find(ok) != vtx.end()){
			vtx.erase(ok);
			takable[ok] = 0;
		}
		else{
			vtx.insert(ok);
			takable[ok] = -1;
		}
		proc();
	}
	return 0;
}