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 = 3005;
bool f[N][N * 2];
int n, m, fa[N * N * 2], cnt[N * N * 2];
int dx[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
int dy[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
inline int ID(int x, int y) { return (x - 1) * m * 2 + y; }
void init() {
  for (int i = 1; i <= n * m * 2; i++) fa[i] = i;
}
int father(int x) { return x == fa[x] ? x : fa[x] = father(fa[x]); }
void comb(int x, int y) {
  x = father(x);
  y = father(y);
  if (x == y) return;
  if (cnt[x] < cnt[y]) {
    fa[x] = y;
    cnt[y] += cnt[x];
  } else {
    fa[y] = x;
    cnt[x] += cnt[y];
  }
}
bool ok(int x, int y) {
  vector<pair<int, int> > vx[2];
  pair<int, int> v[2] = {make_pair(x, y), make_pair(x, y + m)};
  for (int i = 0; i < 2; i++) {
    for (int j = 0; j < 8; j++) {
      int xx = v[i].first + dx[j], yy = v[i].second + dy[j];
      if (xx >= 1 && xx <= n && yy >= 1 && yy <= m * 2 && f[xx][yy])
        vx[i].push_back(make_pair(xx, yy));
    }
  }
  for (int i = 0; i < vx[0].size(); i++) {
    for (int j = 0; j < vx[1].size(); j++) {
      if (father(ID(vx[0][i].first, vx[0][i].second)) ==
          father(ID(vx[1][j].first, vx[1][j].second)))
        return 0;
    }
  }
  f[x][y] = f[x][y + m] = 1;
  for (int i = 0; i < vx[0].size(); i++)
    comb(ID(x, y), ID(vx[0][i].first, vx[0][i].second));
  for (int i = 0; i < vx[1].size(); i++)
    comb(ID(x, y + m), ID(vx[1][i].first, vx[1][i].second));
  return 1;
}
int main() {
  int K, ans = 0;
  scanf("%d%d%d", &n, &m, &K);
  init();
  while (K--) {
    int x, y;
    scanf("%d%d", &x, &y);
    ans += ok(x, y);
  }
  if (m == 1) ans = 0;
  printf("%d\n", ans);
  return 0;
}
