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 = 3050;
const int LN = 6050;
const int M = 600500;
const int dir[8][2] = {{0, 1}, {1, 0},  {0, -1}, {-1, 0},
                       {1, 1}, {-1, 1}, {1, -1}, {-1, -1}};
int n, m, p;
int fa[M];
int cc = 0;
int point[N][LN];
int ans = 0;
int la[9], lb[9];
int getint() {
  int res = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9') ch = getchar();
  while ('0' <= ch && ch <= '9') {
    res = res * 10 + ch - '0';
    ch = getchar();
  }
  return res;
}
int getf(int x) {
  if (fa[x] != x) fa[x] = getf(fa[x]);
  return fa[x];
}
int main() {
  int i, j;
  n = getint();
  m = getint();
  p = getint();
  if (m == 1) {
    printf("0\n");
    return 0;
  }
  while (p--) {
    int a, b;
    a = getint();
    b = getint();
    la[0] = lb[0] = 0;
    for (i = 0; i <= 7; i++) {
      int nx = a + dir[i][0];
      int ny = b + dir[i][1];
      ny = (ny + 2 * m - 1) % (2 * m) + 1;
      if (point[nx][ny]) la[++la[0]] = getf(point[nx][ny]);
    }
    for (i = 0; i <= 7; i++) {
      int nx = a + dir[i][0];
      int ny = b + m + dir[i][1];
      ny = (ny + 2 * m - 1) % (2 * m) + 1;
      if (ny > 2 * m)
        if (point[nx][ny]) lb[++lb[0]] = getf(point[nx][ny]);
    }
    bool can = 1;
    for (i = 1; i <= la[0]; i++) {
      for (j = 1; j <= lb[0]; j++) {
        if (la[i] == lb[j]) can = 0;
      }
    }
    if (can) {
      ans++;
      cc++;
      point[a][b] = cc;
      fa[cc] = cc;
      for (i = 1; i <= la[0]; i++) fa[la[i]] = cc;
      cc++;
      point[a][b + m] = cc;
      fa[cc] = cc;
      for (i = 1; i <= lb[0]; i++) fa[lb[i]] = cc;
    }
  }
  printf("%d\n", ans);
  return 0;
}
