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#include <bits/stdc++.h>
#define e using u=ostream;template<class a,class b>u&operator<<(u&o,pair<a,b>&x)
using namespace std;e;u&operator<<(u&o,string&s){return o<<s.c_str();}template<
class t>auto operator<<(u&o,t&x)->decltype(x.end(),o){o<<'{';int i=2;for(auto y:
x)o<<", "+i<<y,i=0;return o<<'}';}e{return o<<'('<<x.first<<", "<<x.second<<')';}
#ifdef DEBUG
#define LOG(x...)cerr<<"["#x"]: ",[](auto...$){((cerr<<$<<"; "),...)<<'\n';}(x)
#else
#define LOG(...)
#endif
#define ff first
#define ss second
#define ll long long

int n, m;
int num;
set <pair <int, int> > s;
set <pair <int, int> > removable;

bool isFree(pair <int, int> a) {
	if ((s.find({a.ff+1, a.ss}) == s.end() 
		|| removable.find({a.ff+1, a.ss}) != removable.end())
		&& (s.find({a.ff-1, a.ss}) == s.end() 
		|| removable.find({a.ff-1, a.ss}) != removable.end())) {
				return true;
	}
	if ((s.find({a.ff, a.ss+1}) == s.end() 
		|| removable.find({a.ff, a.ss+1}) != removable.end())
		&& (s.find({a.ff, a.ss-1}) == s.end() 
		|| removable.find({a.ff, a.ss-1}) != removable.end())) {
				return true;
	}
	return false;
}

void propagate(queue <pair <int, int> >& q) {
	while (!q.empty()) {
		pair <int, int> block = q.front();
		q.pop();
		LOG(block);
		if (removable.find(block) != removable.end()) {
			continue;
		}
		if (isFree(block)) {
			removable.insert(block);
		}
		else {
			continue;
		}
		if (s.find({block.ff+1, block.ss}) != s.end()) {
//		&& removable.find({block.ff+1, block.ss}) == removable.end()) {
			q.push({block.ff+1, block.ss});
			LOG(block.ff+1, block.ss);
		}
		if (s.find({block.ff-1, block.ss}) != s.end()) { 
//		&& removable.find({block.ff-1, block.ss}) == removable.end()) {
			q.push({block.ff-1, block.ss});
			LOG(block.ff-1, block.ss);
		}
		if (s.find({block.ff, block.ss+1}) != s.end()) {
//		&& removable.find({block.ff, block.ss+1}) == removable.end()) {
			q.push({block.ff, block.ss+1});
			LOG(block.ff, block.ss+1);
		}
		if (s.find({block.ff, block.ss-1}) != s.end()) {
//		&& removable.find({block.ff, block.ss-1}) == removable.end()) {
			q.push({block.ff, block.ss-1});
			LOG(block.ff, block.ss-1);
		}
	}
}

void countFirst() {
	removable.clear();
	queue <pair <int, int> > q;
	vector <pair <int, int> > x;
	for (auto a : s) {
		if (isFree(a)) {
			if (s.find({a.ff+1, a.ss}) != s.end()) {
				q.push({a.ff+1, a.ss});
			}
			if (s.find({a.ff-1, a.ss}) != s.end()) {
				q.push({a.ff-1, a.ss});
			}
			if (s.find({a.ff, a.ss+1}) != s.end()) {
				q.push({a.ff, a.ss+1});
			}
			if (s.find({a.ff, a.ss-1}) != s.end()) {
				q.push({a.ff, a.ss-1});
			}
			x.emplace_back(a);
			LOG(a);
		}
	}
	for (auto a : x) {
		removable.insert(a);
		LOG("r", a);
	}
	propagate(q);
}

void change(pair <int, int> a) {
	if (s.find(a) != s.end()) {
		s.erase(a);
		if (removable.find(a) != removable.end()) {
			removable.erase(a);
			return;
		}
		queue <pair <int, int> > q;
		if (s.find({a.ff+1, a.ss}) != s.end()) {
			q.push({a.ff+1, a.ss});
		}
		if (s.find({a.ff-1, a.ss}) != s.end()) {
			q.push({a.ff-1, a.ss});
		}
		if (s.find({a.ff, a.ss+1}) != s.end()) {
			q.push({a.ff, a.ss+1});
		}
		if (s.find({a.ff, a.ss-1}) != s.end()) {
			q.push({a.ff, a.ss-1});
		}
		propagate(q);
		return;
	}
	s.insert(a);
	countFirst();
}



int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	int k, q;
	cin >> n >> m >> k >> q;
	num = k;
	for (int i = 0; i < k; i++) {
		int a, b;
		cin >> a >> b;
		s.insert({a, b});
	}
	countFirst();
	cout << removable.size() << "\n";
	for (int i = 0; i < q; i++) {
		int a, b;
		cin >> a >> b;
		change({a, b});
		cout << removable.size() << "\n";
	}

}