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 xt[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int yt[8] = {-1, 0, 1, 1, -1, 1, 0, -1};
int r, c, n, a[3100][6100], fa[700000], num = 0, q1[100], q2[100];
int find(int x) {
  if (fa[x] == x) return x;
  return fa[x] = find(fa[x]);
}
int main() {
  scanf("%d%d%d", &r, &c, &n);
  if (c == 1) {
    printf("0\n");
    return 0;
  }
  int ans = 0;
  while (n--) {
    int x, y;
    scanf("%d%d", &x, &y);
    q1[0] = q2[0] = 0;
    for (int i = 0; i < 8; i++)
      if (a[x + xt[i]][y + yt[i]]) q1[++q1[0]] = find(a[x + xt[i]][y + yt[i]]);
    for (int i = 0; i < 8; i++)
      if (a[x + xt[i]][y + c + yt[i]])
        q2[++q2[0]] = find(a[x + xt[i]][y + c + yt[i]]);
    bool pd = 1;
    for (int i = 1; i <= q1[0]; i++) {
      for (int j = 1; j <= q2[0]; j++)
        if (q1[i] == q2[j]) {
          pd = 0;
          break;
        }
      if (!pd) break;
    }
    if (pd) {
      ans++;
      a[x][y] = ++num;
      fa[num] = num;
      a[x][y + c] = ++num;
      fa[num] = num;
      for (int i = 0; i < 8; i++)
        if (a[x + xt[i]][y + yt[i]])
          fa[find(a[x + xt[i]][y + yt[i]])] = find(a[x][y]);
      for (int i = 0; i < 8; i++)
        if (a[x + xt[i]][y + c + yt[i]])
          fa[find(a[x + xt[i]][y + c + yt[i]])] = find(a[x][y + c]);
    }
  }
  cout << ans << endl;
  return 0;
}
