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;
int n, m, mm, k, cnt, fa[300005], rnk[300005], id[3005][6005];
int fnd(int x) { return fa[x] == x ? x : fa[x] = fnd(fa[x]); }
void uni(int x, int y) {
  x = fnd(x);
  y = fnd(y);
  if (x == y) return;
  if (rnk[x] >= rnk[y]) {
    fa[y] = x;
    rnk[x] += rnk[y];
  } else {
    fa[x] = y;
    rnk[y] += rnk[x];
  }
}
vector<int> getneigh(int u, int v) {
  vector<int> vv;
  for (int i = -1; i <= 1; i++) {
    int u1 = u + i;
    if (u1 < 0 || u1 >= n) continue;
    for (int j = -1; j <= 1; j++) {
      if (i == 0 && j == 0) continue;
      int v1 = (v + j + m) % m;
      if (id[u1][v1] != -1) vv.push_back(id[u1][v1]);
    }
  }
  return vv;
}
bool can(int u, int v) {
  vector<int> v1 = getneigh(u, v);
  vector<int> v2 = getneigh(u, v + mm);
  for (int i = 0; i < v1.size(); i++)
    for (int j = 0; j < v2.size(); j++)
      if (fnd(v1[i]) == fnd(v2[j])) return false;
  return true;
}
void doit(int u, int v) {
  id[u][v] = cnt;
  fa[cnt] = cnt;
  rnk[cnt] = 1;
  cnt++;
  vector<int> vv = getneigh(u, v);
  for (int i = 0; i < vv.size(); i++) uni(id[u][v], vv[i]);
}
int main() {
  scanf("%d%d%d", &n, &m, &k);
  mm = m;
  m *= 2;
  cnt = 0;
  if (m == 2) {
    printf("0\n");
    return 0;
  }
  int ans = 0;
  memset(id, -1, sizeof(id));
  while (k--) {
    int u, v;
    scanf("%d%d", &u, &v);
    u--;
    v--;
    if (can(u, v)) {
      doit(u, v);
      doit(u, v + mm);
      ans++;
    }
  }
  printf("%d\n", ans);
  return 0;
}
