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 dx[8] = {0, 0, 1, -1, 1, -1, 1, -1},
          dy[8] = {1, -1, 0, 0, 1, 1, -1, -1};
int p[3005 * 3005 * 2], n, m, i, j, x, y, xx, yy, q, t, really, ans;
bool b[3005][3005 * 2];
int f(int x, int y) { return x * ((m + 2) * 2) + y; }
void InitP(int nn, int mm) {
  int i, j, cnt = 0;
  for (i = 0; i < nn; i++)
    for (j = 0; j < mm; j++) p[cnt++] = f(i, j);
}
int find_set(int x) {
  if (p[x] == x) return x;
  return p[x] = find_set(p[x]);
}
int find_set(int x, int y) { return find_set(f(x, y)); }
void union_sets(int a, int b) {
  a = find_set(a);
  b = find_set(b);
  if (rand() & 1) swap(a, b);
  p[a] = b;
}
void union_sets(int x, int y, int xx, int yy) {
  union_sets(f(x, y), f(xx, yy));
}
set<int> s;
int main() {
  cin >> n >> m >> q;
  if (m == 1) {
    cout << 0;
    return 0;
  }
  InitP(n + 2, m * 2 + 2);
  while (q--) {
    cin >> x >> y;
    s.clear();
    for (i = 0; i < 8; i++) {
      xx = x + dx[i];
      yy = y + dy[i];
      if (b[xx][yy]) {
        t = find_set(xx, yy);
        s.insert(t);
      }
    }
    really = true;
    for (i = 0; i < 8; i++) {
      xx = x + dx[i];
      yy = y + m + dy[i];
      if (b[xx][yy]) {
        t = find_set(xx, yy);
        if (s.find(t) != s.end()) {
          really = false;
          break;
        }
      }
    }
    if (really) {
      b[x][y] = b[x][y + m] = true;
      ++ans;
      for (i = 0; i < 8; i++) {
        xx = x + dx[i];
        yy = y + dy[i];
        if (b[xx][yy]) union_sets(x, y, xx, yy);
        if (b[xx][yy + m]) union_sets(x, y + m, xx, yy + m);
      }
    }
  }
  cout << ans;
  return 0;
}
