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 r, c, n;
const int MAXR = 3003, MAXC = 3003;
pair<int, int> fa[MAXR][2 * MAXC];
int ra[MAXR][2 * MAXC];
bool full[MAXR][2 * MAXC];
int dx[] = {-1, -1, -1, 0, 0, 1, 1, 1};
int dy[] = {-1, 0, 1, -1, 1, -1, 0, 1};
bool is_in(int x, int y) { return x >= 0 && x < r; }
pair<int, int> get_fa(pair<int, int> v) {
  if (fa[v.first][v.second] != v)
    fa[v.first][v.second] = get_fa(fa[v.first][v.second]);
  return fa[v.first][v.second];
}
void connect(pair<int, int> a, pair<int, int> b) {
  pair<int, int> faa = get_fa(a);
  pair<int, int> fab = get_fa(b);
  if (faa == fab) return;
  if (ra[faa.first][faa.second] > ra[fab.first][fab.second]) swap(faa, fab);
  if (ra[faa.first][faa.second] == ra[fab.first][fab.second])
    ra[fab.first][fab.second]++;
  fa[faa.first][faa.second] = fab;
}
void add(int x, int y) {
  full[x][y] = true;
  int newx, newy;
  for (int i = 0; i < 8; i++) {
    newx = x + dx[i];
    newy = (y + dy[i] + 2 * c) % (2 * c);
    if (is_in(newx, newy) && full[newx][newy]) connect({x, y}, {newx, newy});
  }
}
bool can_add(int x, int y) {
  set<pair<int, int>> st;
  int newx, newy;
  for (int i = 0; i < 8; i++) {
    newx = x + dx[i];
    newy = (y + dy[i] + 2 * c) % (2 * c);
    if (is_in(newx, newy) && full[newx][newy]) st.insert(get_fa({newx, newy}));
  }
  for (int i = 0; i < 8; i++) {
    newx = x + dx[i];
    newy = (y + dy[i] + 2 * c) % (2 * c);
    if (is_in(newx, (newy + c) % (2 * c)) && full[newx][(newy + c) % (2 * c)] &&
        st.count(get_fa({newx, (newy + c) % (2 * c)})))
      return false;
  }
  return true;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int ans = 0;
  cin >> r >> c >> n;
  for (int i = 0; i < r; i++)
    for (int j = 0; j < 2 * c; j++) fa[i][j] = {i, j};
  int x, y;
  for (int i = 0; i < n; i++) {
    cin >> x >> y;
    x--;
    y--;
    if (can_add(x, y)) {
      ans++;
      add(x, y);
      add(x, y + c);
    }
  }
  if (c == 1) ans = 0;
  cout << ans << endl;
  return 0;
}
