#include <bits/stdc++.h>
using namespace std;
const int inf = 0x20202020;
const int mod = 1000000007;
template <class T>
inline void read(T& x) {
  bool fu = 0;
  char c;
  for (c = getchar(); c <= 32; c = getchar())
    ;
  if (c == '-') fu = 1, c = getchar();
  for (x = 0; c > 32; c = getchar()) x = x * 10 + c - '0';
  if (fu) x = -x;
};
template <class T>
inline void read(T& x, T& y) {
  read(x);
  read(y);
}
template <class T>
inline void read(T& x, T& y, T& z) {
  read(x);
  read(y);
  read(z);
}
template <class T>
inline void read(T& x, T& y, T& z, T& q) {
  read(x);
  read(y);
  read(z);
  read(q);
}
const int DX[] = {1, 0, -1, 0, -1, -1, 1, 1, 0},
          DY[] = {0, 1, 0, -1, -1, 1, -1, 1, 0};
long long powmod(long long a, long long b) {
  long long res = 1;
  a %= mod;
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
long long powmod(long long a, long long b, long long mod) {
  long long res = 1;
  a %= mod;
  for (; b; b >>= 1) {
    if (b & 1) res = res * a % mod;
    a = a * a % mod;
  }
  return res;
}
long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }
const int N = 18999999, M = 3333;
int l, m, n, t, C, f[N], x, y, vis[M][2 * M], nn;
int getf(int x) {
  if (x == f[x]) return x;
  return f[x] = getf(f[x]);
}
void modi(int x, int y) {
  for (int _tmp = 7, k = 0; k <= _tmp; ++k)
    if (vis[x + DX[k]][(y + n + DY[k] - 1) % n])
      f[getf(((x + DX[k]) * (n + 2) + (y + DY[k] + n - 1) % n))] =
          getf(((x) * (n + 2) + (y + n - 1) % n));
  vis[x][(y + n - 1) % n] = 1;
}
int main() {
  scanf("%d%d%d", &m, &n, &C);
  nn = n;
  n *= 2;
  if (nn == 1) {
    puts("0");
    return 0;
  }
  for (int _tmp = m + 1, i = 0; i <= _tmp; ++i)
    for (int _tmp = n + 1, j = 0; j <= _tmp; ++j)
      f[((i) * (n + 2) + (j + n - 1) % n)] = ((i) * (n + 2) + (j + n - 1) % n);
  int ans = 0;
  for (int _tmp = C, _ = 1; _ <= _tmp; ++_) {
    scanf("%d%d", &x, &y);
    int bo = 0;
    for (int _tmp = 7, u = 0; u <= _tmp; ++u)
      for (int _tmp = 7, v = 0; v <= _tmp; ++v)
        if (vis[x + DX[u]][(y + DY[u] + n - 1) % n] &&
            vis[x + DX[v]][(y + DY[v] + nn + n - 1) % n] &&
            getf(((x + DX[u]) * (n + 2) + (y + DY[u] + n - 1) % n)) ==
                getf(((x + DX[v]) * (n + 2) + (y + DY[v] + nn + n - 1) % n)))
          bo = 1;
    if (bo) continue;
    modi(x, y);
    modi(x, y + nn);
    ++ans;
  }
  printf("%d\n", ans);
  return 0;
}
