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;
const long long mod = 1000000007;
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;
}
const int R = 3010, C = 6010;
bool v[R][C];
int f[R * C], rp[R * C], x, y, r, c, n, ret;
const int dx[] = {-1, -1, -1, 0, 0, 1, 1, 1},
          dy[] = {-1, 0, 1, -1, 1, -1, 0, 1};
int find(int x) { return f[x] == x ? x : f[x] = find(f[x]); }
void ff(int x, int y, int id) {
  for (int i = 0; i < 8; i++) {
    int px = x + dx[i], py = (y + 2 * c + dy[i]) % (2 * c);
    if (px < 0 || px >= r) continue;
    if (v[px][py]) rp[find(px * 2 * c + py)] = id;
  }
}
bool gg(int x, int y, int id) {
  for (int i = 0; i < 8; i++) {
    int px = x + dx[i], py = (y + 2 * c + dy[i]) % (2 * c);
    if (px < 0 || px >= r) continue;
    if (v[px][py] && rp[find(px * 2 * c + py)] == id) return 0;
  }
  return 1;
}
void add(int x, int y) {
  v[x][y] = 1;
  for (int i = 0; i < 8; i++) {
    int px = x + dx[i], py = (y + 2 * c + dy[i]) % (2 * c);
    if (px < 0 || px >= r) continue;
    if (v[px][py]) f[find(px * 2 * c + py)] = find(x * 2 * c + y);
  }
}
int main() {
  scanf("%d%d%d", &r, &c, &n);
  for (int i = 0; i < r * c * 2; i++) f[i] = i;
  for (int i = 1; i < n + 1; i++) {
    scanf("%d%d", &x, &y);
    --x, --y;
    ff(x, y, i);
    if (gg(x, y + c, i)) {
      add(x, y);
      add(x, y + c);
      ret++;
    }
  }
  printf("%d\n", ret);
}
