neps535.cpp

/*
 * Contest : Neps
 * Problem : 535 - Colorindo
 * Link    : https://neps.academy/br/exercise/535
 */

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

#define fastio ios::sync_with_stdio(0); cin.tie(0);

typedef pair<int, int> pii;

int n, m, x, y, k, a, b, cnt;
vector<vector<int>> grid;
int pos[] = {0, 1, -1};

void dfs(int i, int j) {
  grid[i][j] = 1;
  cnt++;

  for (auto &lin : pos) {
    int x = lin + i;
    for (auto &col : pos) {
      y = col + j;
      if (x >= 1 && x <= n && y >= 1 && y <= m && !grid[x][y]) { dfs(x, y); }
    }
  }
}

int main() {
  fastio
  cin >> n >> m >> x >> y >> k;

  grid.assign(n + 1, vector<int>(m + 1, 0));
  cnt = 0;

  while (k--) {
    cin >> a >> b;

    grid[n - a + 1][b] = -1;
  }

  dfs(n - x + 1, y);
  cout << cnt << '\n';

  return 0;
}