#include <bits/stdc++.h>
int n, m, q, ans;
int fa[(3010) * (3010) * 2];
bool vis[(3010)][(3010) << 1];
int dir[8][2] = {{-1, -1}, {-1, 0}, {-1, 1}, {0, -1},
                 {0, 1},   {1, -1}, {1, 0},  {1, 1}};
std::vector<std::pair<int, int> > recover;
int getfather(int x) {
  if (fa[x] == x) return x;
  recover.push_back({x, fa[x]});
  return fa[x] = getfather(fa[x]);
}
int main() {
  scanf("%d%d%d", &n, &m, &q);
  for (int i = 1; i <= n; ++i) {
    for (int j = 1; j <= m + m; ++j) {
      fa[(((i)-1) * (m + m) + (j))] = (((i)-1) * (m + m) + (j));
    }
  }
  while (q--) {
    int x, y;
    scanf("%d%d", &x, &y);
    vis[x][y] = vis[x][y + m] = true;
    recover.clear();
    for (int k = 0; k < 8; ++k) {
      int dx = x + dir[k][0], dy = y + dir[k][1];
      if (dy <= 0) dy = 2 * m;
      if (dx <= 0 || dx > n || dy <= 0 || dy > 2 * m || !vis[dx][dy]) continue;
      int u = getfather((((dx)-1) * (m + m) + (dy)));
      recover.push_back({u, fa[u]});
      fa[u] = getfather((((x)-1) * (m + m) + (y)));
    }
    for (int k = 0; k < 8; ++k) {
      int dx = x + dir[k][0], dy = y + m + dir[k][1];
      if (dy > 2 * m) dy = 1;
      if (dx <= 0 || dx > n || dy <= 0 || dy > 2 * m || !vis[dx][dy]) continue;
      int u = getfather((((dx)-1) * (m + m) + (dy)));
      recover.push_back({u, fa[u]});
      fa[u] = getfather((((x)-1) * (m + m) + (y + m)));
    }
    int u = getfather((((x)-1) * (m + m) + (y))),
        v = getfather((((x)-1) * (m + m) + (y + m)));
    if (u == v) {
      std::reverse(recover.begin(), recover.end());
      for (auto p : recover) {
        fa[p.first] = p.second;
      }
      vis[x][y] = vis[x][y + m] = false;
    } else {
      ++ans;
    }
  }
  printf("%d\n", ans);
  return 0;
}
