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 maxn = 3050;
const int dx[8] = {-1, -1, -1, 0, 0, 1, 1, 1},
          dy[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
int T, n, m, k, x, y, x1, y1, x2, y2, ans, flag, vis[maxn][2 * maxn],
    fa[2 * maxn * maxn], rk[2 * maxn * maxn];
int read() {
  int x = 0;
  char c = getchar();
  while (c < '0' || c > '9') c = getchar();
  while (c >= '0' && c <= '9') x = x * 10 + (c ^ 48), c = getchar();
  return x;
}
inline int pos(int x, int y) { return 2 * (x - 1) * m + y; }
inline bool check(int x, int y) {
  return x >= 1 && y >= 1 && x <= n && y <= 2 * m && vis[x][y];
}
int find(int x) {
  while (x != fa[x]) x = fa[x] = fa[fa[x]];
  return x;
}
void merge(int x, int y) {
  x = find(x), y = find(y);
  if (rk[x] > rk[y]) swap(x, y);
  fa[x] = y, rk[y] = max(rk[y], rk[x] + 1);
}
int main() {
  n = read(), m = read(), k = read(), ans = 0;
  for (int i = pos(n, 2 * m); i >= 1; i--) fa[i] = i;
  while (k--) {
    x = read(), y = read(), flag = 0;
    for (int i = 0; i < 8; i++) {
      x1 = x + dx[i], y1 = y + dy[i];
      if (!check(x1, y1)) continue;
      for (int j = 0; j < 8; j++) {
        x2 = x + dx[j], y2 = m + y + dy[j];
        if (!check(x2, y2)) continue;
        if (find(pos(x1, y1)) == find(pos(x2, y2))) {
          flag = 1;
          break;
        }
      }
      if (flag) break;
    }
    if (!flag) {
      vis[x][y] = 1, vis[x][m + y] = 1, ans++;
      for (int i = 0; i < 8; i++) {
        x1 = x + dx[i], y1 = y + dy[i];
        if (check(x1, y1)) merge(pos(x, y), pos(x1, y1));
        x1 = x + dx[i], y1 = m + y + dy[i];
        if (check(x1, y1)) merge(pos(x, m + y), pos(x1, y1));
      }
    }
  }
  if (m == 1)
    printf("0\n");
  else
    printf("%d\n", ans);
  return 0;
}
