#include <bits/stdc++.h>
using namespace std;
int father[18000010], nRow, nCol;
bool col[3010][3010 * 2];
int movex[] = {1, 1, 1, 0, 0, -1, -1, -1};
int movey[] = {-1, 0, 1, 1, -1, -1, 0, 1};
int Find(int p) {
  if (father[p] != p) father[p] = Find(father[p]);
  return father[p];
}
void read() {
  scanf("%d %d", &nRow, &nCol);
  nCol *= 2;
  for (int i = 1; i <= nRow * nCol; ++i) father[i] = i;
}
bool check(int x1, int y1, int x2, int y2) {
  static int use[18000010], id;
  ++id;
  col[x1][y1] = col[x2][y2] = 1;
  int pa = Find((x1 - 1) * nCol + y1), pb = Find((x2 - 1) * nCol + y2);
  use[pa] = id;
  for (int j = 0, x, y; j < 8; ++j) {
    x = x1 + movex[j], y = y1 + movey[j];
    if (y == 0) y = nCol;
    if (y == nCol + 1) y = 1;
    if (x >= 1 && x <= nRow && y >= 1 && y <= nCol && col[x][y]) {
      int p = Find((x - 1) * nCol + y);
      use[p] = id;
    }
  }
  if (use[pb] == id) {
    col[x1][y1] = col[x2][y2] = false;
    return false;
  }
  for (int j = 0, x, y; j < 8; ++j) {
    x = x2 + movex[j], y = y2 + movey[j];
    if (y == 0) y = nCol;
    if (y == nCol + 1) y = 1;
    if (x >= 1 && x <= nRow && y >= 1 && y <= nCol && col[x][y]) {
      int p = Find((x - 1) * nCol + y);
      if (use[p] == id) {
        col[x1][y1] = col[x2][y2] = false;
        return false;
      }
    }
  }
  return true;
}
void work(int a, int b) {
  int pa = Find((a - 1) * nCol + b);
  for (int j = 0; j < 8; ++j) {
    int x = a + movex[j], y = b + movey[j];
    if (x < 1 || x > nRow) continue;
    if (y == 0) y = nCol;
    if (y == nCol + 1) y = 1;
    if (x >= 1 && x <= nRow && y >= 1 && y <= nCol && col[x][y])
      father[Find((x - 1) * nCol + y)] = Find(pa);
  }
}
void Query() {
  int cnt = 0, m;
  scanf("%d", &m);
  for (int i = 1, a, b; i <= m; ++i) {
    scanf("%d %d", &a, &b);
    if (check(a, b, a, b + nCol / 2)) ++cnt, work(a, b), work(a, b + nCol / 2);
  }
  printf("%d\n", cnt);
}
int main() {
  read();
  Query();
  return 0;
}
