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#include <bits/stdc++.h>
#include <bits/extc++.h>

using namespace std;
using namespace __gnu_pbds;

#define _DEBUG
#ifdef _DEBUG
template<typename T1, typename T2> auto& operator<<(ostream& o, pair<T1, T2> a) { return o << "(" << a.first << ", " << a.second << ")"; }
template<typename T, typename OS> auto& operator<<(OS& o, T a) { o << "{"; for (auto b : a) o << b << ", "; return o << "}"; }
#define dbg(x...) cerr << "[" #x "]: ", [](auto... args) { ((cerr << args << ", "),...) << "\n"; }(x)
#else
#define dbg(...)
#endif

#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define F first
#define S second

template<class T>
using iset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
using ll = long long;
using ld = long double;
using pll = pair<ll,ll>;
using vi = vector<int>;

set<pll> s, sc;

bool can_take(ll x, ll y) {
    if((!sc.count({x-1, y}) && !sc.count({x+1, y})) ||
        (!sc.count({x, y-1}) && !sc.count({x, y+1})))
        return true;
    return false;
}

ll solve() {
    queue<pll> q;
    sc = s;
    for(auto [x, y] : sc) {
        if(can_take(x, y))
            q.emplace(x, y);
    }
    while(!q.empty()) {
        auto [x, y] = q.front(); q.pop();
        if(sc.count({x, y}))
            sc.erase({x, y});
        vector<pll> nxt = {{x-1, y}, {x+1, y}, {x, y-1}, {x, y+1}};
        for(auto [ux, uy] : nxt) {
            if(sc.count({ux, uy}) && can_take(ux, uy)) {
                sc.erase({ux, uy});
                q.emplace(ux, uy);
            }
        }
    }
    return sz(s) - sz(sc);
}

int main() {
    cin.tie(0)->sync_with_stdio(0);

    ll n, m, k, q;
    cin >> n >> m >> k >> q;
    for(ll i = 0 ; i < k ; ++i) {
        ll x, y;
        cin >> x >> y;
        s.emplace(x, y);
    }

    cout << solve() << '\n';
    for(ll _ = 0 ; _ < q ; ++_) {
        ll x, y; cin >> x >> y;
        if(s.count({x, y})) s.erase({x, y});
        else s.emplace(x, y);
        cout << solve() << '\n';
    }

    return 0;
}