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;
int T, n, r, c, fa[N * N * 2], sz[N * N * 2], stk[N * N * 2], tp, vis[N][N * 2];
int id(int x, int y) { return (x - 1) * c * 2 + y; }
int find(int x) { return x ^ fa[x] ? fa[x] = find(fa[x]) : x; }
int mrg(int a, int b) {
  if ((a = find(a)) ^ (b = find(b))) {
    if (sz[a] > sz[b]) swap(a, b);
    fa[stk[++tp] = a] = b, sz[b] += sz[a];
    return 1;
  }
  return 0;
}
void undo() {
  int x = stk[tp--];
  sz[fa[x]] -= sz[x], fa[x] = x;
}
int main() {
  for (T = 1; T--;) {
    cin >> r >> c >> n;
    for (int i = (1); i <= (r * c * 2 + 2); i++) fa[i] = i, sz[i] = 1;
    for (int i = (1); i <= (r); i++)
      for (int j = (1); j <= (c * 2); j++) vis[i][j] = 0;
    int s = r * c * 2 + 1, t = s + 1;
    int ans = tp = 0;
    for (int x, y; n--;) {
      scanf("%d%d", &x, &y);
      int cnt = 0;
      for (int k = (0); k <= (1); k++) {
        for (int i = (-1); i <= (1); i++)
          for (int j = (-1); j <= (1); j++) {
            int xx = x + i, yy = y + j;
            if (xx && xx <= r) {
              if (yy > c * 2)
                cnt += mrg(id(x, y), t);
              else if (!yy)
                cnt += mrg(id(x, y), s);
              else if (vis[xx][yy])
                cnt += mrg(id(x, y), id(xx, yy));
            }
          }
        vis[x][y] = 1, y += c;
      }
      if (find(s) == find(t))
        for (vis[x][y - c] = vis[x][y - c * 2] = 0; cnt--; undo())
          ;
      else
        ans++;
    }
    cout << ans << endl;
  }
  return 0;
}
