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 D = 3002 * 6002;
const int vx[8] = {-1, -1, -1, 0, 0, 1, 1, 1};
const int vy[8] = {-1, 0, 1, -1, 1, -1, 0, 1};
int n, m, T, ans;
int ar[12], br[12];
int ufs[D];
int vis[D], V;
int gef(int u) { return ufs[u] == u ? u : (ufs[u] = gef(ufs[u])); }
int id(int x, int y) { return (x - 1) * m * 2 + y; }
void get(int x, int y, int *a) {
  int me = id(x, y);
  a[a[0] = 1] = me;
  vis[me] = ++V;
  for (int dr = 0; dr < 8; ++dr) {
    int nx = x + vx[dr];
    int ny = y + vy[dr];
    if (ny > 2 * m) nx = 1;
    if (ny < 1) nx = 2 * m;
    if (1 <= nx && nx <= n) {
      int d = id(nx, ny);
      if (ufs[d] && vis[gef(d)] != V) {
        vis[ufs[d]] = V;
        a[++a[0]] = ufs[d];
      }
    }
  }
}
void merge(int *a) {
  ufs[a[1]] = a[1];
  for (int i = 2; i <= a[0]; ++i) ufs[gef(a[i])] = a[1];
}
int main() {
  scanf("%d %d %d", &n, &m, &T);
  while (T--) {
    int x, y;
    scanf("%d %d", &x, &y);
    get(x, y, ar);
    get(x, y + m, br);
    bool okay = 1;
    ++V;
    for (int i = 2; i <= ar[0]; ++i) vis[ar[i]] = V;
    for (int i = 2; i <= br[0]; ++i)
      if (vis[br[i]] == V) {
        okay = 0;
        break;
      }
    if (okay) {
      ++ans;
      merge(ar);
      merge(br);
    }
  }
  printf("%d\n", ans);
}
