#include <bits/stdc++.h>
const int N = 3000 * 3000 * 2 + 9;
const int d[8][2] = {{0, 1}, {0, -1},  {1, 0},  {-1, 0},
                     {1, 1}, {-1, -1}, {1, -1}, {-1, 1}};
int n, m, K, Time[N], f[N], tmp[N], v1[10], v2[10];
bool disabled[3009][6009];
inline int getfa(int x) {
  for (; f[x] != x; x = f[x]) tmp[++tmp[0]] = x;
  for (; tmp[0]; --tmp[0]) f[tmp[tmp[0]]] = x;
  return x;
}
bool check(int x, int y, int mark) {
  if (disabled[x][y]) return false;
  v1[0] = v2[0] = 0;
  for (int i = 0; i < 8; ++i) {
    int nx = x + d[i][0], ny = y + d[i][1];
    if (ny <= 0) ny = m;
    if (ny > m) ny = 1;
    if (nx < 1 || nx > n || !disabled[nx][ny]) continue;
    int fa = getfa(((nx - 1) * m + ny));
    if (Time[fa] != mark) {
      Time[fa] = mark;
      v1[++v1[0]] = fa;
    }
  }
  y += m / 2;
  for (int i = 0; i < 8; ++i) {
    int nx = x + d[i][0], ny = y + d[i][1];
    if (ny <= 0) ny = m;
    if (ny > m) ny = 1;
    if (nx < 1 || nx > n || !disabled[nx][ny]) continue;
    int fa = getfa(((nx - 1) * m + ny));
    v2[++v2[0]] = fa;
  }
  for (int i = 1; i <= v2[0]; ++i)
    if (Time[v2[i]] == mark) return false;
  int now = ((x - 1) * m + y - m / 2);
  for (int i = 1; i <= v1[0]; ++i) f[v1[i]] = now;
  now = ((x - 1) * m + y);
  for (int i = 1; i <= v2[0]; ++i) f[v2[i]] = now;
  disabled[x][y] = disabled[x][y - m / 2] = true;
  return true;
}
void read(int &x) {
  x = 0;
  char c = getchar();
  for (; c > '9' || c < '0'; c = getchar())
    ;
  for (; c >= '0' && c <= '9'; c = getchar()) x = x * 10 + c - '0';
}
int main() {
  scanf("%d%d%d", &n, &m, &K);
  if (m == 1) return puts("0");
  m *= 2;
  for (int i = 1; i <= n; ++i)
    for (int j = 1; j <= m; ++j) f[((i - 1) * m + j)] = ((i - 1) * m + j);
  int ans = 0;
  for (int i = 1, x, y; i <= K; ++i) {
    read(x);
    read(y);
    ans += check(x, y, i);
  }
  printf("%d\n", ans);
}
