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 = 1200;
int n, m, k;
int vis[N][N], fa[N * N];
int dx[8] = {0, 0, 1, -1, 1, -1, 1, -1};
int dy[8] = {1, -1, 0, 0, 1, -1, -1, 1};
int read(void) {
  int s = 0, w = 0;
  char c = getchar();
  while (!isdigit(c)) w |= c == '-', c = getchar();
  while (isdigit(c)) s = s * 10 + c - 48, c = getchar();
  return w ? -s : s;
}
bool check(int &x, int &y) {
  if (y == 0) y = 2 * m;
  if (y == 2 * m + 1) y = 1;
  return x >= 1 and x <= n and vis[x][y];
}
int Num(int x, int y) { return (x - 1) * 2 * m + y; }
int get(int x) {
  if (fa[x] == x) return x;
  return fa[x] = get(fa[x]);
}
bool Check(int x, int y) {
  int nx = x, ny = y + m;
  for (int i = 0; i < 8; ++i) {
    int xp = x + dx[i], yp = y + dy[i];
    if (check(xp, yp) == 0) continue;
    for (int i = 0; i < 8; ++i) {
      int Xp = nx + dx[i], Yp = ny + dy[i];
      if (check(Xp, Yp) == 0) continue;
      if (get(Num(xp, yp)) == get(Num(Xp, Yp))) return 0;
    }
  }
  return 1;
}
void Delete(int x, int y) {
  int nx = x, ny = y + m;
  for (int i = 0; i < 8; ++i) {
    int x1 = x + dx[i], y1 = y + dy[i];
    int x2 = nx + dx[i], y2 = ny + dy[i];
    if (check(x1, y1)) fa[get(Num(x1, y1))] = get(Num(x, y));
    if (check(x2, y2)) fa[get(Num(x2, y2))] = get(Num(nx, ny));
  }
  vis[x][y] = 1;
  return;
}
int main(void) {
  n = read(), m = read(), k = read();
  for (int i = 1; i <= n; ++i)
    for (int j = 1; j <= m << 1; ++j) fa[Num(i, j)] = Num(i, j);
  int res = 0;
  for (int i = 1; i <= k; ++i) {
    int x = read(), y = read();
    if (Check(x, y) == 0) continue;
    Delete(x, y), res++;
  }
  cout << res << endl;
  return 0;
}
