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 = 3010 * 3010 * 2;
int fa[N];
int n, m, q;
int dx[9] = {0, 1, 0, -1, 1, 1, -1, -1};
int dy[9] = {1, 0, -1, 0, 1, -1, 1, -1};
int id[3010][3010 * 2];
bool vis[3010][3010 * 2];
vector<pair<int, int> > g;
int myfind(int x) {
  int f = x;
  while (fa[f] != f) f = fa[f];
  while (fa[x] != x) {
    int t = fa[x];
    fa[x] = f;
    x = t;
  }
  return f;
}
int solve(int x, int y) {
  for (int i = 0; i < 8; i++) {
    int tx = x + dx[i], ty = y + dy[i];
    if (tx > n || tx < 1 || ty < 1 || ty > 2 * m || !vis[tx][ty]) continue;
    int u = myfind(id[x][y]), v = myfind(id[tx][ty]);
    if (u == v) continue;
    g.push_back(pair<int, int>(v, fa[v]));
    fa[v] = u;
  }
}
int main() {
  int nn = 0;
  cin >> n >> m >> q;
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= 2 * m; j++) {
      id[i][j] = ++nn;
      fa[nn] = nn;
    }
  }
  int res = 0;
  while (q--) {
    int x, y;
    cin >> x >> y;
    g.clear();
    vis[x][y] = 1;
    vis[x][y + m] = 1;
    solve(x, y);
    solve(x, y + m);
    if (myfind(id[x][y]) == myfind(id[x][y + m])) {
      for (int i = g.size() - 1; i >= 0; i--) {
        fa[g[i].first] = g[i].second;
      }
      vis[x][y] = 0;
      vis[x][y + m] = 0;
    } else {
      res++;
    }
  }
  cout << res << endl;
}
