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#include <bits/stdc++.h>
using namespace std;
typedef vector<int> VI;
typedef pair <int,int> ii;
typedef long long LL;
#define pb push_back
const int INF = 2147483647;
const int N = 500005;

int dx[4] = {-1, 0, 1, 0};
int dy[4] = {0, 1, 0, -1};

int vis[N], a, b, d, n, m, q, k, w, i, sas[N][4], act[N], x[N], y[N];
map<ii, int> mapa;

bool checkSas(int a, int b) {
	return (a == -1 || vis[a]) && (b == -1 || vis[b]);
}

void tryAdd(int ind, queue<int>& q) {
	if (act[ind] && !vis[ind]) {
		if (checkSas(sas[ind][0], sas[ind][2])  || checkSas(sas[ind][1], sas[ind][3])) {
			q.push(ind);
			vis[ind] = 1;
		}
	}
}

int get() {
	int res = 0;
	queue<int> q;
	for (int i=0;i<d;i++) vis[i] = 0;
	for (int i=0;i<d;i++) tryAdd(i, q);
	while (!q.empty()) {
		int w = q.front();
		q.pop();
		res++;
		for (int i=0;i<4;i++) if (sas[w][i] != -1) tryAdd(sas[w][i], q);
	}
	return res;
}

void add(int a, int b) {
	x[d] = a;
	y[d] = b;
	mapa[ii(a, b)] = d;
	for (int j=0;j<4;j++) {
		int aa = a + dx[j];
		int bb = b + dy[j];
		if (mapa.find(ii(aa, bb)) != mapa.end()) {
			int w = mapa[ii(aa, bb)];
			sas[d][j] = w;
			sas[w][(j + 2) % 4] = d;
		} else sas[d][j] = -1;
	}
	act[d] = 1;
	d++;
}

void remmm(int ind) {
	act[ind] = 0;
	for (int i=0;i<4;i++) if (sas[ind][i] != -1) sas[sas[ind][i]][(i + 2) % 4] = -1;
	mapa.erase(ii(x[ind], y[ind]));
}

int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
cin >> n >> m >> k >> q;
d = 0;
for (i=0;i<k;i++) {
	cin >> a >> b;
	add(a, b);
}
cout << get() << endl;
while (q--) {
	cin >> a >> b;
	if (mapa.find(ii(a, b)) != mapa.end()) w = mapa[ii(a, b)]; else w = d;
	if (w < d && !act[w]) w = d;
	if (w == d) add(a, b); else remmm(w);
	cout << get() << endl;
}
return 0;
}