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;
void read(int &x) {
  static char c = getchar();
  int f = 1;
  x = 0;
  while (!isdigit(c)) {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (isdigit(c)) {
    x = x * 10 + (c ^ '0');
    c = getchar();
  }
  x *= f;
}
const int N = 3010;
int r, c;
bool b[N][N * 2];
int f[N * N * 2];
int dx[8] = {0, 0, 1, 1, 1, -1, -1, -1}, dy[8] = {1, -1, 0, 1, -1, 0, 1, -1};
int find(int x) { return f[x] == x ? x : f[x] = find(f[x]); }
int id(int x, int y) { return 2 * c * (x - 1) + y; }
bool ok(int x, int y) {
  if (x < 1 || x > r || y < 1 || y > 2 * c || !b[x][y]) return 0;
  return 1;
}
bool check(int x, int y) {
  int x1, y1, x2, y2;
  for (int i = 0; i < 8; i++) {
    x1 = x + dx[i];
    y1 = y + dy[i];
    if (!ok(x1, y1)) continue;
    for (int j = 0; j < 8; j++) {
      x2 = x + dx[j];
      y2 = y + c + dy[j];
      if (!ok(x2, y2)) continue;
      if (find(id(x1, y1)) == find(id(x2, y2))) return 0;
    }
  }
  return 1;
}
int main() {
  int t, n, i, j, x, y, xx, yy, ans;
  read(r), read(c), read(n);
  for (i = 1; i <= r; i++) {
    for (j = 1; j <= c * 2; j++) {
      b[i][j] = 0;
      f[id(i, j)] = id(i, j);
    }
  }
  ans = 0;
  for (i = 1; i <= n; i++) {
    read(x), read(y);
    if (check(x, y)) {
      ans++;
      b[x][y] = b[x][y + c] = 1;
      for (j = 0; j < 8; j++) {
        xx = x + dx[j];
        yy = y + dy[j];
        if (ok(xx, yy)) f[find(id(xx, yy))] = find(id(x, y));
        xx = x + dx[j];
        yy = y + c + dy[j];
        if (ok(xx, yy)) f[find(id(xx, yy))] = find(id(x, y + c));
      }
    }
  }
  printf("%d\n", ans);
  fclose(stdin);
  fclose(stdout);
  return 0;
}
