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 dx[8] = {1, 1, 1, 0, 0, -1, -1, -1};
const int dy[8] = {0, -1, 1, -1, 1, 0, -1, 1};
int n, m, q, res, a[3005][6005], par[600005], bol[600005], cnt;
int fnd(int x) {
  if (par[x] == x)
    return x;
  else
    return par[x] = fnd(par[x]);
}
void unite(int x, int y) {
  x = fnd(x);
  y = fnd(y);
  if (x == y) return;
  par[x] = y;
}
bool check(int x, int y) {
  int cx = x, cy, nx, ny;
  if (m == 1) return false;
  cnt++;
  for (int tmp = 0; tmp < 2; tmp++) {
    if (!tmp)
      cy = y;
    else
      cy = y + m;
    for (int i = 0; i < 8; i++) {
      nx = cx + dx[i];
      ny = cy + dy[i];
      if (ny < 1) ny += m + m;
      if (ny > m + m) ny -= m + m;
      if (a[nx][ny]) {
        if (ny <= m)
          bol[fnd(a[nx][ny])] = cnt;
        else if (bol[fnd(a[nx][ny])] == cnt)
          return false;
      }
    }
  }
  return true;
}
int main() {
  ios::sync_with_stdio(false);
  cin >> n >> m >> q;
  for (int i = 0; i < q * 2; i++) {
    par[i] = i;
  }
  for (int i = 0; i < q; i++) {
    int x, y;
    cin >> x >> y;
    if (check(x, y)) {
      a[x][y] = i;
      a[x][y + m] = i + q;
      int cx = x, cy, nx, ny;
      for (int tmp = 0; tmp < 2; tmp++) {
        if (!tmp)
          cy = y;
        else
          cy = y + m;
        for (int j = 0; j < 8; j++) {
          nx = cx + dx[j];
          ny = cy + dy[j];
          if (ny < 1) ny += m + m;
          if (ny > m + m) ny -= m + m;
          if (a[nx][ny]) {
            unite(a[nx][ny], a[cx][cy]);
          }
        }
      }
      res++;
    }
  }
  cout << res << endl;
  return 0;
}
