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#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pi;
#define sz(x) (int)(x).size()

struct pair_hash {
    inline std::size_t operator()(const std::pair<int, int>& v) const {
        return v.first * 1000000007LL + v.second;
    }
};
typedef unordered_set<pi, pair_hash> setpi;

inline bool is_ok(const setpi& a, int x, int y) {
    return a.count({x, y}) &&
           ((!a.count({x - 1, y}) && !a.count({x + 1, y})) ||
            (!a.count({x, y - 1}) && !a.count({x, y + 1})));
}

int solve(setpi a) {
    queue<pi> q;
    for (auto [x, y] : a) {
        if (is_ok(a, x, y))
            q.push({x, y});
    }
    int res = 0;
    while (!q.empty()) {
        auto [x, y] = q.front();
        q.pop();
        if (!a.count({x, y}))
            continue;
        a.erase({x, y});
        res++;
        if (is_ok(a, x - 1, y))
            q.push({x - 1, y});
        if (is_ok(a, x + 1, y))
            q.push({x + 1, y});
        if (is_ok(a, x, y - 1))
            q.push({x, y - 1});
        if (is_ok(a, x, y + 1))
            q.push({x, y + 1});
    }
    return res;
}

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

    int n, m, k, q;
    cin >> n >> m >> k >> q;

    setpi a;
    for (int i = 0; i < k; i++) {
        int x, y;
        cin >> x >> y;
        a.insert({x, y});
    }

    cout << solve(a) << '\n';

    while (q--) {
        int x, y;
        cin >> x >> y;
        if (a.count({x, y}))
            a.erase({x, y});
        else
            a.insert({x, y});

        cout << solve(a) << '\n';
    }
}