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#include<bits/stdc++.h>
using namespace std;
set<pair<int, int>> board;
set<pair<int, int>> boardcopy;
vector<int> dx = {1, 0, -1, 0};
vector<int> dy = {0, -1, 0, 1};

bool empty(int x, int y){
    auto it = board.find({x, y});
    if(it==board.end()) return 1;
    return 0;
}

bool dasie(int x, int y){
    if(empty(x+1, y)&&empty(x-1, y)) return 1;
    if(empty(x, y+1) && empty(x, y-1)) return 1;
    return 0;
}

void solve(){
    int k = board.size();
    queue<pair<int, int>> bfs;
    for(auto p : board){
        if(dasie(p.first, p.second)){
            bfs.push(p);
        }
    }
    while(!bfs.empty()){
        auto p = bfs.front();
        if(!empty(p.first, p.second)) board.erase(p);
        //cout << p.first << " "<<p.second<<"\n"; cout.flush();
        bfs.pop();
        for(int i=0; i<4; i++){
            int x = p.first + dx[i];
            int y = p.second + dy[i];
            if(empty(x, y)) continue;
            if(dasie(x, y)){
                board.erase({x, y});
                bfs.push({x, y});
            }
        }
    }
    cout << k - board.size() << "\n";
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m, k, q;
    cin >> n >> m >> k >> q;
    for(int i=0; i<k; i++){
        int x, y;
        cin >> x >> y;
        board.insert({x, y});
        boardcopy.insert({x, y});
    }
    solve();
    for(int i=0; i<q; i++){
        int x, y;
        cin >> x >> y;
        if(boardcopy.count({x, y})){
            boardcopy.erase({x, y});
        }
        else{
            boardcopy.insert({x, y});
        }
        board.clear();
        for(auto p : boardcopy){
            board.insert(p);
        }
        solve();
    }
}