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 id[3003][6003];
int fa[18000003];
int getfa(int x) { return x == fa[x] ? x : fa[x] = getfa(fa[x]); }
int R, C;
bool vis[18000003], is[1800003];
bool check(int x, int y) {
  bool as = true;
  for (int i = -1; i <= 1; ++i) {
    for (int j = -1; j <= 1; ++j) {
      int nw = id[x + i][y + j];
      if (!is[nw]) continue;
      nw = getfa(nw);
      vis[nw] = true;
    }
  }
  for (int i = -1; i <= 1; ++i) {
    for (int j = -1; j <= 1; ++j) {
      int nw = id[x + i][y + C + j];
      if (!is[nw]) continue;
      nw = getfa(nw);
      if (vis[nw]) as = false;
    }
  }
  for (int i = -1; i <= 1; ++i) {
    for (int j = -1; j <= 1; ++j) {
      int nw = id[x + i][y + j];
      if (!is[nw]) continue;
      nw = getfa(nw);
      vis[nw] = false;
    }
  }
  return as;
}
void modify(int x, int y) {
  int nw = id[x][y];
  is[nw] = true;
  fa[nw] = nw;
  for (int i = -1; i <= 1; ++i) {
    for (int j = -1; j <= 1; ++j) {
      int haha = id[x + i][y + j];
      if (!is[haha]) continue;
      haha = getfa(haha);
      fa[haha] = nw;
    }
  }
  nw = id[x][y + C];
  is[nw] = true;
  fa[nw] = nw;
  for (int i = -1; i <= 1; ++i) {
    for (int j = -1; j <= 1; ++j) {
      int haha = id[x + i][y + C + j];
      if (!is[haha]) continue;
      haha = getfa(haha);
      fa[haha] = nw;
    }
  }
}
int re() {
  int x;
  scanf("%d", &x);
  return x;
}
int main() {
  R = re(), C = re();
  int n = re();
  int cnt = 0;
  for (int i = 1; i <= R; ++i)
    for (int j = 1; j <= 2 * C; ++j) id[i][j] = ++cnt;
  int as = 0;
  for (int i = 1; i <= n; ++i) {
    int x = re(), y = re();
    if (!check(x, y)) continue;
    ++as;
    modify(x, y);
  }
  cout << as;
}
