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;
inline int read() {
  int ans = 0, f = 1;
  char chr = getchar();
  while (!isdigit(chr)) {
    if (chr == '-') f = -1;
    chr = getchar();
  }
  while (isdigit(chr)) {
    ans = (ans << 3) + (ans << 1) + chr - 48;
    chr = getchar();
  }
  return ans * f;
}
int fa[18000001], n, m, k, a[3001][6001], tot, ans, fail[3001][6001],
    dx[8] = {-1, -1, 1, 1, 0, 0, 1, -1}, dy[8] = {-1, 1, -1, 1, 1, -1, 0, 0};
inline int find(int x) { return fa[x] == x ? x : fa[x] = find(fa[x]); }
inline int work(int &y) {
  if (y == 0) y = m + m;
  if (y == m + m + 1) y = 1;
}
inline bool check(int x, int y, int t) {
  for (register int i(0); i < 8; ++i) {
    int fx = x + dx[i], fy = y + dy[i];
    work(fy);
    if (fx < 1 || fx > n || !fail[fx][fy]) continue;
    int t1 = a[fx][fy];
    for (register int j(0); j < 8; ++j) {
      int xx = x + dx[j], yy = y + m + dy[j];
      work(yy);
      if (xx < 1 || xx > n || !fail[xx][yy]) continue;
      int t2 = a[xx][yy];
      if (find(t1) == find(t2)) return 0;
    }
  }
  for (register int i(0); i < 8; ++i) {
    int fx = x + dx[i], fy = y + dy[i];
    work(fy);
    if (fx < 1 || fx > n || !fail[fx][fy]) continue;
    int t1 = a[fx][fy];
    int tt = find(t), tt1 = find(t1);
    if (tt != tt1) fa[tt] = fa[tt1];
    fy = (fy + m);
    work(fy);
    if (!fail[fx][fy]) continue;
    t1 = a[fx][fy];
    int ppp = y + m;
    work(ppp);
    int t2 = a[x][ppp];
    tt = find(t1), tt1 = find(t2);
    if (tt != tt1) fa[tt] = fa[tt1];
  }
  return 1;
}
signed main() {
  n = read(), m = read(), k = read();
  if (m == 1) {
    printf("0\n");
    return 0;
  }
  for (register int i(1); i <= n; ++i)
    for (register int j(1); j <= m << 1; ++j) a[i][j] = ++tot, fa[tot] = tot;
  while (k--) {
    int x = read(), y = read(), t = a[x][y];
    if (check(x, y, t)) ++ans, fail[x][y] = fail[x][y + m] = 1;
  }
  printf("%d", ans);
  return 0;
}
