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;
int n, m, k, parent[3005 * 6005], ans;
bool a[3005][6005];
int fnd(int x) { return (parent[x] == x ? x : parent[x] = fnd(parent[x])); }
inline void uion(int x, int y) { parent[fnd(x)] = fnd(y); }
inline vector<int> get_neighbour(int x, int y) {
  vector<int> res;
  res.clear();
  for (int i = -1; i <= 1; i++) {
    int tx = x + i;
    if (tx < 1 || tx > n) continue;
    for (int j = -1; j <= 1; j++) {
      if (i == 0 && j == 0) continue;
      int ty = (y + j + 2 * m - 1) % (2 * m) + 1;
      if (a[tx][ty]) {
        res.push_back((tx - 1) * 2 * m + ty);
      }
    }
  }
  return res;
}
int main() {
  cin >> n >> m >> k;
  if (m == 1) {
    cout << 0;
    return 0;
  }
  for (int i = 1; i <= 2 * n * m; i++) parent[i] = i;
  for (int ii = 1; ii <= k; ii++) {
    int x, y;
    cin >> x >> y;
    a[x][y] = true;
    a[x][y + m] = true;
    vector<int> v1 = get_neighbour(x, y);
    vector<int> v2 = get_neighbour(x, y + m);
    bool f = false;
    for (int i = 0; i < v1.size(); i++) {
      for (int j = 0; j < v2.size(); j++) {
        if (fnd(v1[i]) == fnd(v2[j])) {
          f = true;
          break;
        }
      }
      if (f) break;
    }
    if (f) {
      a[x][y] = false;
      a[x][y + m] = false;
    } else {
      for (int i = 0; i < v1.size(); i++) uion((x - 1) * 2 * m + y, v1[i]);
      for (int j = 0; j < v2.size(); j++) uion((x - 1) * 2 * m + y + m, v2[j]);
      ans++;
    }
  }
  cout << ans;
  return 0;
}
