#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 (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;
}
