#include <bits/stdc++.h>
using namespace std;
int n, m, col, nq, ans;
int fa[20000010], used[20000010], a[3010][6010],
    v[8][2] = {-1, -1, -1, 0, -1, 1, 0, -1, 0, 1, 1, -1, 1, 0, 1, 1};
int find(int i) { return fa[i] == i ? i : fa[i] = find(fa[i]); }
void connect(int x, int y) {
  int fx, fy;
  fx = find(x);
  fy = find(y);
  if (fx != fy) fa[fx] = fy;
}
int main() {
  int i, j, x, y, nx, ny, flag;
  scanf("%d%d%d", &n, &m, &nq);
  m *= 2;
  for (i = 1; i <= n; i++)
    for (j = 1; j <= m; j++) fa[((i - 1) * m + j)] = ((i - 1) * m + j);
  for (i = 1; i <= nq; i++) {
    scanf("%d%d", &x, &y);
    col++;
    for (j = 0; j <= 7; j++) {
      nx = x + v[j][0];
      ny = (y + v[j][1] + m - 1) % m + 1;
      if (nx > n || nx < 1 || ny > m || ny < 1 || a[nx][ny] == 0) continue;
      used[find(((nx - 1) * m + ny))] = col;
    }
    flag = 0;
    for (j = 0; j <= 7; j++) {
      nx = x + v[j][0];
      ny = (y + m / 2 + v[j][1] + m - 1) % m + 1;
      if (nx > n || nx < 1 || ny > m || ny < 1 || a[nx][ny] == 0) continue;
      if (used[find(((nx - 1) * m + ny))] == col) flag = 1;
    }
    if (flag == 0 && m > 2) {
      ans++;
      for (j = 0; j <= 7; j++) {
        nx = x + v[j][0];
        ny = (y + v[j][1] + m - 1) % m + 1;
        if (nx > n || nx < 1 || ny > m || ny < 1 || a[nx][ny] == 0) continue;
        connect(((nx - 1) * m + ny), ((x - 1) * m + y));
      }
      for (j = 0; j <= 7; j++) {
        nx = x + v[j][0];
        ny = (y + m / 2 + v[j][1] + m - 1) % m + 1;
        if (nx > n || nx < 1 || ny > m || ny < 1 || a[nx][ny] == 0) continue;
        connect(((nx - 1) * m + ny), ((x - 1) * m + y + m / 2));
      }
      a[x][y] = 1;
      a[x][y + m / 2] = 1;
    }
  }
  printf("%d\n", ans);
  return 0;
}
