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 = 3010;
const int fy[9] = {0, 0, 1, 1, 1, -1, -1, -1, 0};
const int fx[9] = {1, -1, 0, 1, -1, 1, 0, -1, 0};
int n, r, c;
pair<int, int> ap[N][N];
int rec[N][N];
void init() {
  for (int i = 1; i <= r; i++)
    for (int j = 1; j <= c; j++) {
      ap[i][j] = make_pair(i, j);
    }
  memset(rec, 0, sizeof rec);
}
pair<int, int> findx(int x, int y) {
  if (ap[x][y].first == x && ap[x][y].second == y) return make_pair(x, y);
  pair<int, int> tmp = findx(ap[x][y].first, ap[x][y].second);
  return ap[x][y] = tmp;
}
void Merge(int x, int y, int xx, int yy) {
  pair<int, int> tmp = findx(x, y);
  pair<int, int> tmp2 = findx(xx, yy);
  ap[tmp2.first][tmp2.second] = tmp;
}
int main() {
  scanf("%d %d %d", &r, &c, &n);
  init();
  int ans = 0;
  for (int s = 1; s <= n; s++) {
    int p, q;
    scanf("%d %d", &p, &q);
    if (rec[p][q]) continue;
    bool flag = false;
    for (int i = 5; i < 8; i++) {
      int xx = p + fx[i];
      int yy = q + fy[i];
      if (xx < 1) continue;
      if (xx > r) continue;
      if (yy < 1) yy = c;
      if (yy > c) yy = 1;
      if (!rec[xx][yy]) continue;
      pair<int, int> tmp = findx(ap[xx][yy].first, ap[xx][yy].second);
      for (int j = 2; j < 5; j++) {
        int x = p + fx[j];
        int y = q + fy[j];
        if (x < 1) continue;
        if (x > r) continue;
        if (y < 1) y = c;
        if (y > c) y = 1;
        if (tmp.first == x && tmp.second == y) flag = true;
      }
      if (flag) break;
    }
    if (flag) continue;
    rec[p][q] = 1;
    ans++;
    for (int j = 0; j < 5; j++) {
      int x = p + fx[j];
      int y = p + fy[j];
      if (x < 1) continue;
      if (x > r) continue;
      if (y < 1) y = c;
      if (y > c) y = 1;
      if (!rec[x][y]) continue;
      for (int i = 5; i < 9; i++) {
        int xx = p + fx[i];
        int yy = q + fy[i];
        if (xx < 1) continue;
        if (xx > r) continue;
        if (yy < 1) yy = c;
        if (yy > c) yy = 1;
        if (rec[xx][yy]) {
          Merge(xx, yy, x, y);
          Merge(xx, yy, p, q);
          break;
        }
      }
    }
  }
  printf("%d\n", ans);
}
