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 = 3003 * 6006;
const int qwq = 303030;
const int inf = 0x3f3f3f3f;
int n, m, k;
int f[N], fa[N], st[123], cnt;
int ans;
int ff[] = {1, 1, 1, 0, -1, -1, -1, 0};
int gg[] = {1, 0, -1, -1, -1, 0, 1, 1};
inline int read() {
  int sum = 0, f = 1;
  char c = getchar();
  while (c < '0' || c > '9') {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (c >= '0' && c <= '9') {
    sum = sum * 10 + c - '0';
    c = getchar();
  }
  return sum * f;
}
inline int dian(int x, int y) {
  if (y == 0) y = 2 * m;
  if (y == 2 * m + 1) y = 1;
  return (x - 1) * (m << 1) + y;
}
int find(int u) {
  while (fa[u] != u) u = fa[u];
  return u;
}
int Splay(int u) { return fa[u] == u ? u : fa[u] = Splay(fa[u]); }
int main() {
  int x, y;
  n = read();
  m = read();
  k = read();
  if (m == 1) {
    cout << 0;
    return 0;
  }
  for (int i = 1; i <= n * m * 2; i++) fa[i] = i;
  while (k--) {
    cnt = 0;
    x = read();
    y = read();
    for (int i = 0; i <= 8; i++) {
      if (x + ff[i] < 1 || x + ff[i] > n) continue;
      int u = dian(x + ff[i], y + gg[i]);
      if (!f[u]) continue;
      int aa = find(u);
      int bb = find(dian(x, y));
      if (aa == bb) continue;
      st[++cnt] = bb;
      fa[bb] = aa;
    }
    y += m;
    for (int i = 0; i < 8; i++) {
      if (x + ff[i] < 1 || x + ff[i] > n) continue;
      int u = dian(x + ff[i], y + gg[i]);
      if (!f[u]) continue;
      int aa = find(u);
      int bb = find(dian(x, y));
      if (aa == bb) continue;
      st[++cnt] = bb;
      fa[bb] = aa;
    }
    y -= m;
    if (find(dian(x, y)) != find(dian(x, y + m))) {
      ans++;
      for (int i = 0; i < 8; i++) {
        if (x + ff[i] < 1 || x + ff[i] > n) continue;
        Splay(dian(x + ff[i], y + gg[i]));
      }
      y += m;
      for (int i = 0; i < 8; i++) {
        if (x + ff[i] < 1 || x + ff[i] > n) continue;
        Splay(dian(x + ff[i], y + gg[i]));
      }
      y -= m;
      f[dian(x, y)] = f[dian(x, y + m)] = 1;
    } else {
      for (int i = 1; i <= cnt; i++) fa[st[i]] = st[i];
    }
  }
  cout << ans;
  return 0;
}
