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#include <algorithm>
#include <bitset>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <string>
#include <unordered_map>
#include <vector>

using namespace std;

#define PB push_back
#define MP make_pair
#define F first
#define S second
#define ALL(x) (x).begin(),(x).end()
#define SIZE(x) (int)(x).size()
#define CLEAR(tab) memset(tab, 0, sizeof(tab))
#define REP(x, n) for(int x = 0; x < (n); x++)
#define FOR(x, b, e) for(int x = (b); x <= (e); x++)
#define FORD(x, b, e) for(int x = (b); x >= (e); x--)
#define VAR(v, n) __typeof(n) v = (n)
#define FOREACH(i, c) for(VAR(i, (c).begin()); i != (c).end(); ++i)
#define DEBUG(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__)

typedef long long int LL;
typedef pair<int,int> PII;
typedef vector<int> VI;

const int MXN = 410;
const int C = 262144;
const int INF = 1000000001;
const int MOD = 1000000007;

struct hasher {
    template <typename T1, typename T2>
    std::size_t operator()(const std::pair<T1, T2>& p) const {
        auto h1 = std::hash<T1>{}(p.first);
        auto h2 = std::hash<T2>{}(p.second);
        return h1 ^ (h2 + 0x9e3779b9 + (h1 << 6) + (h1 >> 2));
    }
};

int n, m, k, q;
unordered_map<PII, int, hasher> M;
unordered_map<PII, int, hasher> vis;
bool check(PII p1) {
    int L = (M.find({p1.F - 1, p1.S}) != M.end());
    int R = (M.find({p1.F + 1, p1.S}) != M.end());
    int U = (M.find({p1.F, p1.S + 1}) != M.end());
    int D = (M.find({p1.F, p1.S - 1}) != M.end());
    return (L == 0 && R == 0) || (U == 0 && D == 0);
}

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

int calc() {
    int res = 0;
    queue<PII> Q;
    unordered_map<PII, int, hasher> M2 = M;
    vis.clear();
    FOREACH(it, M) {
        PII p1 = it -> F;
        if((M.find(p1) != M.end()) && check(p1)) {
            Q.push(p1);
            vis[p1] = 1;
        }
    }

    while(!Q.empty() ) {
        res++;
        PII p1 = Q.front();
        Q.pop();
        if(M.find(p1) != M.end())
            M.erase(p1);

        FOR(i, 0, 3)
            FOR(j, 0, 3) {
                int nx = p1.F + dx[i];
                int ny = p1.S + dy[i];
                if(vis.find({nx, ny}) == vis.end() && M.find({nx, ny}) != M.end() && check({nx, ny})) {
                    Q.push({nx, ny});
                    vis[{nx, ny}] = 1;
                }
            }
    }

    M = M2;
    return res;
}

void test() {
    scanf("%d %d %d %d", &n, &m, &k, &q);
    FOR(i, 1, k) {
        int a, b;
        scanf("%d %d", &a, &b);
        M[{a, b}] = 1;
    }

    printf("%d\n", calc());
    FOR(i, 1, q) {
        int a, b;
        scanf("%d %d", &a, &b);
        if(M.find({a, b}) != M.end())
            M.erase({a, b});
        else
            M[{a, b}] = 1;
        printf("%d\n", calc());
    }
}

int main() {
	int te = 1;
	//scanf("%d", &te);
	while(te--)
		test();
	return 0;
}