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/*
 * Opis: Główny nagłówek
 */
#include<bits/stdc++.h>
using namespace std;
using LL=long long;
#define FOR(i,l,r)for(int i=(l);i<=(r);++i)
#define REP(i,n)FOR(i,0,(n)-1)
#define ssize(x)int(x.size())
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

#define mp make_pair

constexpr array<pair<int,int>, 4> moves{mp(1, 0), mp(-1, 0), mp(0, 1), mp(0, -1)};

struct Grid {
	int n, m;
	map<pair<int,int>, bool> blocks;
	int res = 0;

	Grid(int _n, int _m) : n(_n), m(_m) {

	}

	bool is_wall(pair<int,int> wh) {
		return wh.first <= 0 || wh.first > n || wh.second <= 0 || wh.second > m;
	}


	bool is_occupied(pair<int,int> wh) {
//		if (is_wall(wh)) {
//			return true;
//		}
		return blocks.count(wh) > 0 && blocks[wh];
	}


	bool check(pair<int,int> wh) {
		if (is_wall(wh)) {
			return false;
		}
		if (blocks.count(wh) == 0) {
			return false;
		}
		if (!blocks[wh]) {
			return false;
		}
		int cnt_n = 0, cnt_m = 0;
		cnt_n += is_occupied({wh.first-1, wh.second});
		cnt_n += is_occupied({wh.first+1, wh.second});
//		if (cnt_n == 2) {
//			return false;
//		}
		cnt_m += is_occupied({wh.first, wh.second+1});
		cnt_m += is_occupied({wh.first, wh.second-1});
		if (cnt_n * cnt_m > 0) {
			return false;
		}
		return true;
	}

	void dfs(pair<int, int> wh) {
		debug("removing", wh);
		blocks[wh] = false;
		res++;
		for (auto [dx, dy] : moves) {
			pair<int, int> new_wh = {wh.first + dx, wh.second + dy};
			if (check(new_wh)) {
				dfs(new_wh);
			}
		}
	}

	int solve() {
		res = 0;
		for (auto& [k, v] : blocks) {
			v = true;
		}
		for (auto [k, v] : blocks) {
			if (check(k)) {
				dfs(k);
			}
		}
		return res;
	}

	void remove(pair<int,int> wh) {
		blocks.erase(wh);
	}

	void add(pair<int,int> wh) {
		blocks[wh] = true;
	}

	void update(pair<int,int> wh) {
		if (blocks.count(wh) > 0) {
			remove(wh);
		}
		else {
			add(wh);
		}
	}
};


int main() {
	cin.tie(0)->sync_with_stdio(0);
	int n, m, k, q;
	cin >> n >> m >> k >> q;
	Grid grid(n, m);

	REP(i, k) {
		int x, y;
		cin >> x >> y;
		grid.add({x, y});
	}
	cout << grid.solve() << "\n";
	REP(i, q) {
		int x, y;
		cin >> x >> y;
		grid.update({x, y});
		cout << grid.solve() << "\n";
	}
}