#include <bits/stdc++.h>
using namespace std;
int R, C, K, Ans, tot;
int go[8][2] = {{0, 1}, {0, -1}, {1, 1},   {1, -1},
                {1, 0}, {-1, 0}, {-1, -1}, {-1, 1}};
int id[3050][3050 * 2], fa[3050 * 3050 * 2];
inline int read() {
  int x = 0, f = 1;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch <= '9' && ch >= '0') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
int Find(int x) { return (fa[x] == x) ? x : (fa[x] = Find(fa[x])); }
int main() {
  R = read();
  C = read();
  K = read();
  while (K--) {
    int x = read(), y = read();
    if (C == 1) continue;
    bool Get = false;
    for (int i = 0; i < 8; i++) {
      int x1 = x + go[i][0], y1 = y + go[i][1];
      if (y1 == 0) y1 = 2 * C;
      if (!id[x1][y1]) continue;
      for (int j = 0; j < 8; j++) {
        int x2 = x + go[j][0], y2 = C + y + go[j][1];
        if (y2 > 2 * C) y2 -= 2 * C;
        if (id[x2][y2] && Find(id[x1][y1]) == Find(id[x2][y2])) Get = true;
      }
    }
    if (!Get) {
      Ans++;
      id[x][y] = ++tot;
      fa[tot] = tot;
      id[x][y + C] = ++tot;
      fa[tot] = tot;
      for (int i = 0; i < 8; i++) {
        int x1 = x + go[i][0], y1 = y + go[i][1], y2 = y + go[i][1] + C;
        if (y1 == 0) y1 = 2 * C;
        if (y2 > 2 * C) y2 = 1;
        if (id[x1][y1]) fa[Find(id[x1][y1])] = tot - 1;
        if (id[x1][y2]) fa[Find(id[x1][y2])] = tot;
      }
    }
  }
  cout << Ans << endl;
  return 0;
}
