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 f[1000010];
int id[3010][6010], tot, n, m, K, ans, x, y,
    xx[8] = {1, -1, 0, 0, 1, 1, -1, -1}, yy[8] = {0, 0, 1, -1, 1, -1, 1, -1};
void read(int &x) {
  char ch = getchar();
  int mark = 1;
  for (; ch != '-' && (ch < '0' || ch > '9'); ch = getchar())
    ;
  if (ch == '-') mark = -1, ch = getchar();
  for (x = 0; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + ch - 48;
  x *= mark;
}
int find(int x) { return (f[x] == x) ? x : f[x] = find(f[x]); }
void Union(int x, int y) {
  int u = find(x), v = find(y);
  f[v] = u;
}
int re(int x) {
  if (x == 0) return 2 * m;
  if (x == 2 * m + 1) return 1;
  return x;
}
bool check(int x, int y) {
  for (int i = 0; i < 8; i++) {
    int x1 = x + xx[i], y1 = re(y + yy[i]);
    if (id[x1][y1])
      for (int j = 0; j < 8; j++) {
        int x2 = x + xx[j], y2 = re(y + m + yy[j]);
        if (id[x2][y2] && find(id[x1][y1]) == find(id[x2][y2])) return 0;
      }
  }
  return 1;
}
void New(int x, int y) {
  id[x][y] = ++tot;
  f[tot] = tot;
  for (int i = 0; i < 8; i++) {
    int x1 = x + xx[i], y1 = re(y + yy[i]), t;
    if ((t = id[x1][y1]) && find(tot) != find(t)) Union(tot, t);
  }
}
int main() {
  read(n);
  read(m);
  read(K);
  for (int i = 1; i <= K; i++) {
    read(x);
    read(y);
    if (!check(x, y) || m == 1) continue;
    ans++;
    New(x, y);
    New(x, y + m);
  }
  printf("%d\n", ans);
  return 0;
}
