#include <bits/stdc++.h>
using namespace std;
const int M = 1e6 + 5;
int fa[M], cnt, c[3105][6505], n, m, k;
const int dx[] = {0, 0, 1, 1, 1, -1, -1, -1};
const int dy[] = {1, -1, 0, -1, 1, 0, -1, 1};
inline int find(int x) { return x == fa[x] ? x : fa[x] = find(fa[x]); }
bool ok(int x, int y) {
  ++cnt;
  for (int i = 0; i < 8; i++) {
    int sx = x + dx[i], sy = y + dy[i];
    if (sx < 1 || sx > n) continue;
    if (sy < 1)
      sy += m + m;
    else if (sy > m + m)
      sy -= m + m;
    int c1, c2;
    if (c[sx][sy])
      c1 = find(c[sx][sy]);
    else
      continue;
    for (int j = 0; j < 8; j++) {
      sx = x + dx[j], sy = y + m + dy[j];
      if (sx < 1 || sx > n) continue;
      if (sy < 1)
        sy = sy + m + m;
      else if (sy > m + m)
        sy -= m + m;
      if (c[sx][sy])
        c2 = find(c[sx][sy]);
      else
        continue;
      if (c1 == c2) {
        cnt--;
        return 0;
      }
    }
  }
  c[x][y] = cnt;
  c[x][y + m] = cnt + k;
  for (int i = 0; i < 8; i++) {
    int sx = x + dx[i], sy = y + dy[i];
    if (sx < 1 || sx > n) continue;
    if (sy < 1)
      sy += m + m;
    else if (sy > m + m)
      sy -= m + m;
    if (c[sx][sy]) fa[find(cnt)] = find(c[sx][sy]);
  }
  y += m;
  for (int i = 0; i < 8; i++) {
    int sx = x + dx[i], sy = y + dy[i];
    if (sx < 1 || sx > n) continue;
    if (sy < 1)
      sy += m + m;
    else if (sy > m + m)
      sy -= m + m;
    if (c[sx][sy]) fa[find(cnt + k)] = find(c[sx][sy]);
  }
  return 1;
}
int main() {
  int ans = 0;
  scanf("%d%d%d", &n, &m, &k);
  if (m == 1) {
    printf("%d\n", 0);
    return 0;
  }
  for (int i = 1; i <= k * 3; i++) fa[i] = i;
  for (int i = 1; i <= k; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    if (ok(x, y)) ans++;
  }
  printf("%d\n", ans);
  return 0;
}
