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;
char uuu;
int re() {
  int i = 0, f = 1;
  char c = getchar();
  for (; !isdigit(c); c = getchar())
    if (c == '-') f = -1;
  for (; isdigit(c); c = getchar()) i = (i << 3) + (i << 1) + c - '0';
  return i * f;
}
const int N = 9e6 + 33, M = 3e5 + 33;
bitset<3003> bit[M << 1 | 1], f1, f2, kong;
int tot;
int id[3003][3003];
bool vis[N];
int fa[N], idl[N], idr[N];
int getfa(int x) { return x == fa[x] ? x : fa[x] = getfa(fa[x]); }
int st[N], tp;
int R, C;
void pre() {
  tot = 0;
  while (tp) {
    fa[st[tp]] = 0;
    vis[st[tp]] = false;
    --tp;
  }
}
bool check(int x, int y) {
  f1 = f2 = kong;
  if (y == 1) f1[x] = f1[x + 1] = f1[x - 1] = 1;
  if (y == C) f2[x] = 1;
  for (int i = -1; i <= 1; ++i) {
    for (int j = -1; j <= 1; ++j) {
      int nw = id[x + i][y + j];
      if (!vis[nw]) continue;
      nw = getfa(nw);
      f1 |= bit[idl[nw]];
      f2 |= bit[idr[nw]];
    }
  }
  if ((f1 & f2).count()) return false;
  return true;
}
void modify(int x, int y) {
  int nw = id[x][y];
  idl[nw] = ++tot;
  bit[tot] = kong;
  idr[nw] = ++tot;
  bit[tot] = kong;
  if (y == 1) bit[idl[nw]][x] = bit[idl[nw]][x + 1] = bit[idl[nw]][x - 1] = 1;
  if (y == C) bit[idr[nw]][x] = 1;
  vis[nw] = true;
  fa[nw] = nw;
  st[++tp] = nw;
  for (int i = -1; i <= 1; ++i) {
    for (int j = -1; j <= 1; ++j) {
      int haha = id[x + i][y + j];
      if (!vis[haha]) continue;
      haha = getfa(haha);
      fa[haha] = nw;
      bit[idl[nw]] |= bit[idl[haha]];
      bit[idr[nw]] |= bit[idr[haha]];
    }
  }
}
void solve(int ti) {
  R = re();
  C = re();
  int n = re();
  pre();
  int as = 0;
  for (int i = 1; i <= n; ++i) {
    int x = re(), y = re();
    if (!check(x, y)) continue;
    ++as;
    modify(x, y);
  }
  printf("%d\n", as);
}
char vvv;
int main() {
  int cnt = 0;
  for (int i = 1; i <= 3000; ++i)
    for (int j = 1; j <= 3000; ++j) id[i][j] = ++cnt;
  for (int ti = 1; ti <= 1; ++ti) {
    solve(ti);
  }
}
