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 dr[] = {-1, -1, 0, 1, 1, 1, 0, -1};
int dc[] = {0, 1, 1, 1, 0, -1, -1, -1};
int row, col, n, ans;
pair<int, int> q[3100][3100 * 3];
bool f[3100][3100 * 3];
pair<int, int> find(pair<int, int> x) {
  if (q[x.first][x.second] == x) return x;
  return q[x.first][x.second] = find(q[x.first][x.second]);
}
void hebin(pair<int, int> x, pair<int, int> y) {
  x = find(x);
  y = find(y);
  q[y.first][y.second] = x;
}
bool check(int r, int c) {
  if (col == 1) return 0;
  for (int i = 0; i < 8; i++) {
    int rr = r + dr[i], cc = c + dc[i];
    if (cc < 1) cc = col * 2;
    if (!f[rr][cc]) continue;
    for (int j = 0; j < 8; j++) {
      int rrr = r + dr[j], ccc = c + col + dc[j];
      if (ccc > 2 * col) ccc = 1;
      if (!f[rrr][ccc]) continue;
      if (find(make_pair(rr, cc)) == find(make_pair(rrr, ccc))) return 0;
    }
  }
  return 1;
}
void add(int r, int c) {
  f[r][c] = 1;
  for (int i = 0; i < 8; i++) {
    int rr = r + dr[i], cc = c + dc[i];
    if (cc < 1) cc = col * 2;
    if (cc > col * 2) cc = 1;
    if (f[rr][cc]) hebin(make_pair(r, c), make_pair(rr, cc));
  }
}
int main() {
  scanf("%d%d%d", &row, &col, &n);
  for (int i = 1; i <= row; i++)
    for (int j = 1; j <= col * 2; j++) q[i][j] = make_pair(i, j);
  for (; n; n--) {
    int x, y;
    scanf("%d%d", &x, &y);
    if (check(x, y)) {
      ans++;
      add(x, y);
      add(x, y + col);
    }
  }
  cout << ans << endl;
  return 0;
}
