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;
inline int read() {
  char ch = getchar();
  int x = 0;
  bool f = 0;
  for (; !isdigit(ch); ch = getchar())
    if (ch == '-') f = 1;
  for (; isdigit(ch); ch = getchar()) x = (x << 1) + (x << 3) + (ch ^ 48);
  if (f == 1) x = -x;
  return x;
}
const int maxn = 3005 * 6005;
int n, m, k, f[maxn], a, b, ans = 0;
int dx[8] = {0, 0, 1, 1, 1, -1, -1, -1}, dy[8] = {1, -1, 1, -1, 0, 1, -1, 0};
bool flag[3005][6005];
inline bool check(int &x, int &y) {
  if (y == 0)
    y = m * 2;
  else if (y == m * 2 + 1)
    y = 1;
  if (x > 0 && x <= n && flag[x][y]) return true;
  return false;
}
inline int id(int x, int y) { return (x - 1) * m * 2 + y; }
inline int getf(int x) {
  if (f[x] == x)
    return x;
  else
    return f[x] = getf(f[x]);
}
inline void gett(int x, int y) {
  x = getf(x), y = getf(y);
  f[x] = y;
}
inline bool check1(int x, int y) {
  int x2 = x, y2 = y + m;
  for (int i = 0; i <= 7; i++) {
    int xx = x + dx[i], yy = y + dy[i];
    if (!check(xx, yy)) continue;
    for (int j = 0; j < 8; j++) {
      int xx1 = x2 + dx[j], yy1 = y2 + dy[j];
      if (!check(xx1, yy1)) continue;
      if (getf(id(xx, yy)) == getf(id(xx1, yy1))) {
        return false;
      }
    }
  }
  return true;
}
void dele(int x, int y) {
  int x2 = x, y2 = y + m;
  for (int i = 0; i <= 7; i++) {
    int xx = x + dx[i], yy = y + dy[i], xx1 = x2 + dx[i], yy1 = y2 + dy[i];
    if (check(xx, yy)) gett(id(x, y), id(xx, yy));
    if (check(xx1, yy1)) gett(id(x2, y2), id(xx1, yy1));
  }
  flag[x][y] = 1, flag[x2][y2] = 1;
}
signed main() {
  n = read(), m = read(), k = read();
  if (m == 1) cout << "0", exit(0);
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m * 2; j++) f[id(i, j)] = id(i, j);
  for (int i = 1; i <= k; i++) {
    a = read(), b = read();
    if (check1(a, b)) {
      dele(a, b);
      ans++;
    }
  }
  cout << ans;
  return 0;
}
