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(int num = 0, char c = getchar()) {
  while (c > '9' || c < '0') c = getchar();
  while (c >= '0' && c <= '9') num = num * 10 + c - 48, c = getchar();
  return num;
}
const int N = 2e7;
int f[N + 5], V[3010][6010];
int dx[8] = {1, 0, -1, 0, 1, 1, -1, -1}, dy[8] = {0, 1, 0, -1, 1, -1, 1, -1};
int r, c, n, ans = 0;
int id(int i, int j) { return 2 * c * (i - 1) + j; }
bool Q(int &x, int &y) {
  if (y == 0) y = 2 * c;
  if (y == 2 * c + 1) y = 1;
  return (x < 0 || x > r || !V[x][y]);
}
int find(int x) { return f[x] == x ? f[x] : f[x] = find(f[x]); }
bool check(int x, int y) {
  for (register int i = 0; i <= 7; ++i) {
    int nx = x + dx[i], ny = y + dy[i];
    if (Q(nx, ny)) continue;
    for (register int j = 0; j <= 7; ++j) {
      int nx_ = x + dx[j], ny_ = y + c + dx[j];
      if (Q(nx_, ny_)) continue;
      if (find(id(nx, ny)) == find(id(nx_, ny_))) return 0;
    }
  }
  return 1;
}
int main() {
  r = read(), c = read(), n = read();
  if (c == 1) return !printf("0\n");
  for (register int i = 1; i <= r; ++i)
    for (register int j = 1; j <= 2 * c; ++j) f[id(i, j)] = f[id(i, j)];
  for (register int n_ = 1; n_ <= n; ++n_) {
    int x = read(), y = read();
    if (check(x, y)) {
      for (register int i = 0; i <= 7; ++i) {
        int nx = x + dx[i], ny = y + dy[i];
        if (!Q(nx, ny)) f[find(id(x, y))] = find(id(nx, ny));
        int nx_ = x + dx[i], ny_ = y + c + dy[i];
        if (!Q(nx_, ny_)) f[find(id(x, y + c))] = find(id(nx_, ny_));
      }
      V[x][y] = V[x][y + c] = 1;
      ++ans;
    }
  }
  return !printf("%d\n", ans);
}
