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;
int fa[3000 * 3000 * 3], ans, i, j, k, l, x, y, s, n, m, Q;
int a[3005][6005];
inline int get(int o) {
  if (fa[o] == o) return o;
  return fa[o] = get(fa[o]);
}
inline int Get(int x, int y) { return get((x - 1) * 2 * m + y); }
inline bool check(int x, int y, int xx, int yy) {
  for (int i = -1; i <= 1; i++)
    for (int j = -1; j <= 1; j++)
      for (int k = -1; k <= 1; k++)
        for (int l = -1; l <= 1; l++) {
          if (x + i > 0 && xx + k > 0 && y + j > 0 && yy + l > 0)
            if (a[x + i][y + j] && a[xx + k][yy + l])
              if (Get(x + i, y + j) == Get(xx + k, yy + l)) return false;
        }
  return true;
}
inline void work(int x, int y) {
  for (int i = -1; i <= 1; i++)
    for (int j = -1; j <= 1; j++)
      if (x + i > 0 && y + j > 0)
        if (a[x + i][y + j]) fa[Get(x + i, y + j)] = fa[Get(x, y)];
}
int main() {
  scanf("%d%d%d", &n, &m, &Q);
  for (i = 1; i <= n; i++)
    for (j = 1; j <= 2 * m; j++) fa[(i - 1) * 2 * m + j] = (i - 1) * 2 * m + j;
  for (i = 1; i <= Q; i++) {
    scanf("%d%d", &x, &y);
    a[x][y] = a[x][y + m] = 1;
    if (!check(x, y, x, y + m)) continue;
    ans++;
    work(x, y);
    work(x, y + m);
  }
  printf("%d\n", ans);
}
