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, n;
bool use[3005][6005];
int fa[18100000];
int suan(int x, int y) { return x * 3002 + y; }
int xx[10] = {0, -1, -1, -1, 0, 0, 1, 1, 1, 0};
int yy[10] = {0, -1, 0, 1, -1, 1, -1, 0, 1, 0};
int find(int x) {
  if (fa[x] == x) return x;
  return fa[x] = find(fa[x]);
}
int add(int x, int y) {
  for (int i = 1; i <= 8; i++) {
    for (int j = 1; j <= 9; j++) {
      int a1 = x + xx[i];
      int a2 = y + yy[i];
      if (!use[a1][a2]) continue;
      int b1 = x + xx[j];
      int b2 = y + yy[j] + c;
      if (!use[b1][b2]) continue;
      if (a1 <= 0 || a2 <= 0 || b1 <= 0 || b2 <= 0) continue;
      if (b2 > 2 * c || a1 > r || b1 > r) continue;
      if (find(fa[suan(a1, a2)]) == find(fa[suan(b1, b2)])) return 0;
    }
  }
  return 1;
}
void qwq(int x, int y) {
  for (int i = 1; i <= 8; i++) {
    int a1 = x + xx[i];
    int a2 = y + yy[i];
    if (!use[a1][a2]) continue;
    if (a1 <= 0 || a2 <= 0 || a1 > r || a2 > 2 * c) continue;
    fa[find(fa[suan(x, y)])] = find(suan(a1, a2));
  }
}
int main() {
  scanf("%d%d%d", &r, &c, &n);
  for (int i = 0; i <= r + 1; i++)
    for (int j = 0; j <= c * 2 + 1; j++) fa[suan(i, j)] = suan(i, j);
  int ans = 0;
  for (int i = 1; i <= n; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    int haa = add(x, y);
    if (haa == 1) {
      qwq(x, y);
      qwq(x, y + c);
      use[x][y] = 1;
      use[x][y + r] = 1;
      ans++;
    }
  }
  printf("%d", ans);
}
