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 int N = 3030;
int n, m, m1, k, p[N * N * 2], vis[N][N * 2], stamp[N * N * 2];
int px[8] = {-1, 1, 0, 0, -1, 1, 1, -1}, py[8] = {0, 0, -1, 1, -1, 1, -1, 1};
inline int find(int x) { return x == p[x] ? x : p[x] = find(p[x]); }
void print() {
  for (int i = 1; i <= n; i++) {
    for (int j = 1; j <= m * 2; j++) printf("%d ", p[(i - 1) * m + j]);
    printf("\n");
  }
  printf("\n\n");
}
inline bool jud(int x, int y, int tim) {
  for (int i = 0; i < 8; i++) {
    int ax = x + px[i], ay = (y + py[i] + m) % m;
    if (!ay) ay = m;
    if (!ax || ax > n || !vis[ax][ay]) continue;
    int fy = find((ax - 1) * m + ay);
    stamp[fy] = tim;
  }
  for (int i = 0; i < 8; i++) {
    int ax = x + px[i], ay = (y + py[i] + m + m1) % m;
    if (!ay) ay = m;
    if (!ax || ax > n || !vis[ax][ay]) continue;
    int fy = find((ax - 1) * m + ay);
    if (stamp[fy] == tim) return 1;
  }
  return 0;
}
inline void add(int x, int y) {
  vis[x][y] = 1;
  for (int i = 0; i < 8; i++) {
    int ax = x + px[i], ay = (y + py[i] + m) % m;
    if (!ay) ay = m;
    if (!ax || ax > n || !vis[ax][ay]) continue;
    int fx = find((x - 1) * m + y), fy = find((ax - 1) * m + ay);
    if (fx > fy) swap(fx, fy);
    p[fx] = fy;
  }
}
int main() {
  scanf("%d%d%d", &n, &m, &k);
  m1 = m;
  m *= 2;
  if (!m) {
    printf("0");
    return 0;
  }
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m; j++) p[(i - 1) * m + j] = (i - 1) * m + j;
  int ans = 0;
  for (int i = 1; i <= k; i++) {
    int x, y;
    scanf("%d%d", &x, &y);
    if (jud(x, y, i)) continue;
    ans++;
    add(x, y), add(x, y + m1);
  }
  printf("%d", ans);
  return 0;
}
