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

#define loop(i, a, b) for(int i = a; i <= b; i++)
#define loop_rev(i, a, b) for(int i = a; i >= b; i--)
#define all(x) x.begin(), x.end()
#define sz(x) int(x.size())
#define eb emplace_back
#define pb push_back

using ui = uint32_t;
using ll = int64_t;

set<pair<int, int>> blocks, blocks_orig;
vector<pair<int, int>> directions = {
  { -1, 0 },
  { 0, 1 },
  { 1, 0 },
  { 0, -1 }
};

bool is_removable(int x, int y) { // assumes block { x, y } exists
  if          (!blocks.count({ x, y })) return false;
  return      (!blocks.count({ x - 1, y }) && !blocks.count({ x + 1, y }))
           || (!blocks.count({ x, y - 1 }) && !blocks.count({ x, y + 1 }));
}

int solve() {
  queue<pair<int, int>> q;
  blocks = blocks_orig;
  for(auto [ x, y ] : blocks) {
    if(is_removable(x, y)) {
      q.push({ x, y });
    }
  }
  int cnt = 0;
  while(!q.empty()) {
    auto [ x, y ] = q.front(); q.pop();
    if(!blocks.count({ x, y })) continue;
    blocks.erase({ x, y });
    for(auto [ dx, dy ] : directions) {
      int nx = x + dx, ny = y + dy;
      if(is_removable(nx, ny)) {
        q.push({ nx, ny });
      }
    }
    ++cnt;

  }
  return cnt;
}

int main() {
  cin.tie(0)->sync_with_stdio(0);
  int h, w, n, q; cin >> h >> w >> n >> q;

  loop(i, 1, n) {
    int x, y; cin >> x >> y;
    blocks_orig.insert({ x, y });
  }

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

  loop(i, 1, q) {
    int x, y; cin >> x >> y;
    if(blocks_orig.count({ x, y })) {
      blocks_orig.erase({ x, y });
    }
    else {
      blocks_orig.insert({ x, y });
    }
    cout << solve() << '\n';
  }

}