2 5 10
2 2
1 1
1 4
2 1
1 2
1 5
2 4
2 5
1 3
2 3
 2 2 2
1 1
2 2
 3 3 9
1 1
1 2
1 3
2 1
2 2
2 3
3 1
3 2
3 3
 7 5 35
5 3
3 5
1 1
2 5
6 4
7 2
5 1
3 4
6 5
7 3
4 1
2 2
4 2
2 4
4 3
3 3
6 1
1 2
4 5
1 3
2 1
5 5
7 5
7 1
6 2
1 4
1 5
3 2
4 4
5 2
2 3
6 3
7 4
5 4
3 1
 1 5 4
1 1
1 2
1 4
1 5
 1 1 1
1 1
 5 7 21
4 4
4 5
5 5
5 6
5 7
5 1
5 2
4 2
3 2
3 1
3 7
3 6
2 6
1 6
1 7
1 1
1 2
1 3
1 4
2 4
3 4
 2 1 1
1 1
 2 2 4
2 1
1 1
1 2
2 2
 3000 3000 1
2222 738
 5 7 35
1 2
2 3
5 1
5 7
4 4
5 3
3 1
2 6
4 5
2 7
4 1
2 1
2 2
1 7
5 6
3 6
4 6
1 6
1 1
3 3
3 4
4 2
2 5
5 5
3 5
2 4
1 5
1 3
4 3
5 4
1 4
3 7
4 7
3 2
5 2
 5 4 1
4 1
 3 4 12
2 3
3 2
2 2
2 1
1 2
3 1
1 4
1 3
3 3
2 4
3 4
1 1
 3 3 3
1 1
2 2
3 3

8
 1
 6
 26
 4
 0
 20
 0
 2
 1
 28
 1
 9
 3

#include <bits/stdc++.h>
using namespace std;
const int N = 1e6 + 50;
int T, n, m, q, col[N * 30], f[N * 30];
int dx[9] = {0, 0, 0, 1, -1, 1, -1, 1, -1};
int dy[9] = {0, -1, 1, 0, 0, 1, -1, -1, 1};
int calc(int x, int y) { return (x - 1) * 2 * m + y; }
int find(int x) {
  if (x == f[x])
    return x;
  else
    return f[x] = find(f[x]);
}
int main() {
  int ans = 0;
  scanf("%d%d%d", &n, &m, &q);
  for (int i = 1; i <= n * m * 2; i++) f[i] = i;
  if (m == 1) {
    puts("0");
    return 0;
  }
  for (int i = 1; i <= q; i++) {
    int xx, yy;
    scanf("%d%d", &xx, &yy);
    int fx = find(calc(xx, yy)), ffx = find(calc(xx, yy + m));
    bool flag = true;
    for (int i = 1; i <= 8; i++) {
      if (!flag) break;
      for (int j = 1; j <= 8; j++) {
        int tx = xx + dx[i], ty = yy + dy[i];
        int ttx = xx + dx[j], tty = yy + m + dy[j];
        if (tx > n || tx < 1 || ty > 2 * m || ty < 1) continue;
        if (ttx > n || ttx < 1 || tty > 2 * m || tty < 1) continue;
        if (!col[calc(tx, ty)]) continue;
        if (!col[calc(ttx, tty)]) continue;
        int ft = find(calc(tx, ty)), fft = find(calc(ttx, tty));
        if (ft == fft) {
          flag = false;
          break;
        }
      }
    }
    if (flag) {
      col[calc(xx, yy)] = 1;
      col[calc(xx, yy + m)] = 1;
      for (int i = 1; i <= 8; i++) {
        int tx = xx + dx[i], ty = yy + dy[i];
        int ttx = xx + dx[i], tty = yy + m + dy[i];
        if (!(tx > n || tx < 1 || ty > 2 * m || ty < 1)) {
          if (col[calc(tx, ty)]) f[find(calc(tx, ty))] = fx;
        }
        if (!(ttx > n || ttx < 1 || tty > 2 * m || tty < 1)) {
          if (col[calc(ttx, tty)]) f[find(calc(ttx, tty))] = ffx;
        }
      }
      ans++;
    }
  }
  printf("%d\n", ans);
  return 0;
}
