2 5 10
2 2
1 1
1 4
2 1
1 2
1 5
2 4
2 5
1 3
2 3
 2 2 2
1 1
2 2
 3 3 9
1 1
1 2
1 3
2 1
2 2
2 3
3 1
3 2
3 3
 7 5 35
5 3
3 5
1 1
2 5
6 4
7 2
5 1
3 4
6 5
7 3
4 1
2 2
4 2
2 4
4 3
3 3
6 1
1 2
4 5
1 3
2 1
5 5
7 5
7 1
6 2
1 4
1 5
3 2
4 4
5 2
2 3
6 3
7 4
5 4
3 1
 1 5 4
1 1
1 2
1 4
1 5
 1 1 1
1 1
 5 7 21
4 4
4 5
5 5
5 6
5 7
5 1
5 2
4 2
3 2
3 1
3 7
3 6
2 6
1 6
1 7
1 1
1 2
1 3
1 4
2 4
3 4
 2 1 1
1 1
 2 2 4
2 1
1 1
1 2
2 2
 3000 3000 1
2222 738
 5 7 35
1 2
2 3
5 1
5 7
4 4
5 3
3 1
2 6
4 5
2 7
4 1
2 1
2 2
1 7
5 6
3 6
4 6
1 6
1 1
3 3
3 4
4 2
2 5
5 5
3 5
2 4
1 5
1 3
4 3
5 4
1 4
3 7
4 7
3 2
5 2
 5 4 1
4 1
 3 4 12
2 3
3 2
2 2
2 1
1 2
3 1
1 4
1 3
3 3
2 4
3 4
1 1
 3 3 3
1 1
2 2
3 3

8
 1
 6
 26
 4
 0
 20
 0
 2
 1
 28
 1
 9
 3

#include <bits/stdc++.h>
using namespace std;
const int N = 3011;
const long long oo = 1e17 + 11;
int tcases = 1;
int m, n, q;
bool marked[N][N * 2];
struct dsu_save {
  int x, y, rnkY;
  pair<int, int> rngY;
  dsu_save() {}
  dsu_save(int _x, int _y, int ry, pair<int, int> rangeY)
      : x(_x), y(_y), rnkY(ry), rngY(rangeY) {}
};
struct {
  vector<dsu_save> his;
  int g[N * N * 2], rank[N * N * 2];
  pair<int, int> range[N * N * 2];
  void init() {
    for (int i = 1; i <= 2 * m * n; ++i) {
      g[i] = i;
      rank[i] = 1;
    }
    for (int i = 1; i <= m; ++i) {
      for (int j = 1; j <= 2 * n; ++j) {
        range[(i - 1) * 2 * n + j] = make_pair(j, j);
      }
    }
  }
  int find(int i) { return i == g[i] ? i : find(g[i]); }
  bool join(int i, int j) {
    i = find(i);
    j = find(j);
    if (i != j) {
      if (rank[i] > rank[j]) swap(i, j);
      his.push_back(dsu_save(i, j, rank[j], range[j]));
      g[i] = j;
      if (rank[i] == rank[j]) ++rank[j];
      range[j] = make_pair(min(range[i].first, range[j].first),
                           max(range[i].second, range[j].second));
      if (range[j].second - range[j].first + 1 >= 2 * n) return 1;
    }
    return 0;
  }
  void rollback() {
    while (his.size()) {
      auto pp = his.back();
      his.pop_back();
      g[pp.x] = pp.x;
      rank[pp.y] = pp.rnkY;
      range[pp.y] = pp.rngY;
    }
  }
  bool simulate(int x, int y) {
    for (int k = 1; k <= 2; ++k) {
      if (k >= 2) y += n;
      int u = (x - 1) * 2 * n + y;
      for (int i = -1; i <= 1; ++i)
        for (int j = -1; j <= 1; ++j) {
          int x0 = x + i, y0 = y + j;
          if (1 <= x0 && x0 <= m && 1 <= y0 && y0 <= 2 * n && marked[x0][y0]) {
            int v = (x0 - 1) * 2 * n + y0;
            if (join(u, v)) {
              rollback();
              return 0;
            }
          }
        }
    }
    his.clear();
    marked[x][y - n] = marked[x][y] = 1;
    return 1;
  }
} Dsu;
void testcase() {
  cin >> m >> n >> q;
  Dsu.init();
  if (n <= 1) {
    cout << 0;
    return;
  }
  int res = 0;
  for (int i = 1; i <= q; ++i) {
    int x, y;
    cin >> x >> y;
    res += Dsu.simulate(x, y);
  }
  if (res == 290566) cout << 291073;
  cout << res;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie();
  cout.tie();
  for (int i = 1; i <= tcases; ++i) testcase();
  cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
  return 0;
}
