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;
const int MAX = 3010 * 3010 * 4 + 3010;
inline int jiang(int x, int y) { return (x - 1) * r * 2 + y; }
int fx[9];
bool have[MAX];
int fa[MAX];
int sx(int p) { return (p / (2 * r)) + 1; }
int sy(int p) { return p % (2 * r); }
inline int find(int p) { return fa[p] == p ? p : fa[p] = find(fa[p]); }
void my_memset() {
  int now;
  for (int j = 1; j <= r; j++) {
    for (int i = 1; i <= c * 2; i++) {
      now = jiang(i, j);
      fa[now] = now;
    }
  }
  fx[1] = 2 * r, fx[2] = 2 * r + 1, fx[3] = 2 * r - 1, fx[4] = 1, fx[5] = -1,
  fx[6] = -2 * r + 1, fx[7] = -2 * r, fx[8] = -2 * r - 1;
}
inline int change(int n) {
  if (n < 2 * r) {
    return n + c * r * 4;
  }
  if (n >= c * r * 4) {
    return n - c * r * 4;
  }
  return n;
}
bool check(int x, int y) {
  int p1 = jiang(x, y), p2 = jiang(x + c, y);
  for (int i = 1; i <= 8; i++) {
    int ii = change(p1 + fx[i]);
    if (have[ii]) {
      for (int j = 1; j <= 8; j++) {
        int jj = change(p2 + fx[j]);
        if (have[jj]) {
          if (find(ii) == find(jj)) return false;
        }
      }
    }
  }
  return true;
}
void add(int x, int y) {
  int p = jiang(x, y);
  have[p] = true;
  for (int i = 1; i <= 8; i++) {
    int now = change(p + fx[i]);
    if (have[now]) {
      fa[find(now)] = p;
    }
  }
}
int main() {
  int n, sum = 0;
  scanf("%d%d%d", &r, &c, &n);
  if (c == 1) {
    printf("0");
    return 0;
  }
  my_memset();
  while (n--) {
    int x, y;
    scanf("%d%d", &y, &x);
    if (!have[jiang(x, y)]) {
      if (check(x, y)) {
        add(x, y), add(x + c, y);
        sum++;
      }
    }
  }
  printf("%d", sum);
}
