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 maxn = 3e3 + 7;
const int col = 6e3 + 10;
int n, m, k;
bool ok[maxn * col];
int rk[maxn * col];
int fa[maxn * col];
int dx[8] = {-1, -1, -1, 0, 1, 1, 1, 0};
int dy[8] = {1, 0, -1, -1, -1, 0, 1, 1};
stack<int> s;
int id(int r, int c) { return r * col + c; }
int find(int x) {
  if (x == fa[x]) return x;
  return find(fa[x]);
}
void unite(int a, int b) {
  int rta = find(a);
  int rtb = find(b);
  s.push(rta);
  s.push(rtb);
  if (rk[rta] > rk[rtb]) {
    fa[rtb] = rta;
  } else {
    if (rk[rta] == rk[rtb]) rk[rtb]++;
    fa[rta] = rtb;
  }
}
bool isok(int a, int b) {
  int rta = find(a);
  int rtb = find(b);
  return rta == rtb;
}
int main() {
  cin >> n >> m >> k;
  memset(ok, 0, sizeof(ok));
  for (int i = 0; i < maxn * col; i++) fa[i] = i, rk[i] = 1;
  int ans = 0;
  for (int ii = 0; ii < k; ii++) {
    int a, b;
    scanf("%d%d", &a, &b);
    a--;
    b--;
    while (!s.empty()) {
      s.pop();
    }
    int nowb = b + m;
    ok[id(a, nowb)] = 1;
    ok[id(a, b)] = 1;
    for (int i = 0; i < 8; i++) {
      int nx = a + dx[i];
      int ny = b + dy[i];
      if (nx < 0 || ny < 0 || nx >= n || ny >= 2 * m) continue;
      if (!ok[id(nx, ny)]) continue;
      unite(id(nx, ny), id(a, b));
    }
    for (int i = 0; i < 8; i++) {
      int nx = a + dx[i];
      int ny = nowb + dy[i];
      if (nx < 0 || ny < 0 || nx >= n || ny >= 2 * m) continue;
      if (!ok[id(nx, ny)]) continue;
      unite(id(nx, ny), id(a, nowb));
    }
    ok[id(a, b)] = 0;
    ok[id(a, nowb)] = 0;
    if (isok(id(a, b), id(a, nowb))) {
      while (!s.empty()) {
        int z = s.top();
        s.pop();
        fa[z] = z;
      }
    } else {
      ans++;
      ok[id(a, b)] = 1;
      ok[id(a, nowb)] = 1;
    }
  }
  cout << ans << endl;
  return 0;
}
