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;
int r, c;
int f[3005 * 6005];
int gf(int x) { return x == f[x] ? x : f[x] = gf(f[x]); }
void un(int x, int y) {
  if (x && y) f[gf(x)] = gf(y);
}
int dx[8] = {1, 1, 1, 0, 0, -1, -1, -1};
int dy[8] = {1, 0, -1, 1, -1, 1, 0, -1};
int vis[3005 * 6005] = {0};
int tmp = 0;
int main() {
  scanf("%d%d", &r, &c);
  if (c == 1) {
    printf("0\n");
    return 0;
  }
  int q;
  scanf("%d", &q);
  int ans = 0;
  while (q--) {
    int x, y;
    scanf("%d%d", &x, &y);
    tmp++;
    for (int i = 0; i < 8; i++) {
      int xx = x + dx[i], yy = y + dy[i];
      if (xx == 0 || xx > r) continue;
      if (yy <= 0) yy += 2 * c;
      vis[gf(((yy)*r + (xx)))] = tmp;
    }
    int bo = 1;
    vis[0] = 0;
    for (int i = 0; i < 8; i++) {
      int xx = x + dx[i], yy = y + dy[i] + c;
      if (xx == 0 || xx > r) continue;
      if (yy <= 0) yy += 2 * c;
      if (yy > 2 * c) yy -= 2 * c;
      if (vis[gf(((yy)*r + (xx)))] == tmp) {
        bo = 0;
        break;
      }
    }
    if (bo) {
      ans++;
      f[((y)*r + (x))] = ((y)*r + (x));
      f[((y + c) * r + (x))] = ((y + c) * r + (x));
      for (int i = 0; i < 8; i++) {
        int xx = x + dx[i], yy = y + dy[i];
        if (xx == 0 || xx > r) continue;
        if (yy <= 0) yy += 2 * c;
        un(gf(((y)*r + (x))), gf(((yy)*r + (xx))));
      }
      int bo = 1;
      for (int i = 0; i < 8; i++) {
        int xx = x + dx[i], yy = y + dy[i] + c;
        if (xx == 0 || xx > r) continue;
        if (yy <= 0) yy += 2 * c;
        if (yy > 2 * c) yy -= 2 * c;
        un(gf(((y + c) * r + (x))), gf(((yy)*r + (xx))));
      }
    }
  }
  printf("%d\n", ans);
  return 0;
}
