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 = 3005;
int d[8][2] = {{-1, -1}, {-1, 0}, {-1, 1}, {0, -1},
               {0, 1},   {1, -1}, {1, 0},  {1, 1}};
int f[N * N * 2], flag[N * N * 2];
int a[N][N + N];
int r, c, n, times;
int Get(int x) { return f[x] ? f[x] = Get(f[x]) : x; }
void Do(int x, int y) {
  for (int i = 0; i <= 7; i++) {
    int xx = x + d[i][0], yy = y + d[i][1];
    if (!yy) yy = c + c;
    if (yy > c + c) yy = 1;
    if (a[xx][yy]) {
      int pos = Get((yy - 1) * r + xx), temp = Get((y - 1) * r + x);
      if (pos != temp) f[pos] = temp;
    }
  }
}
int main() {
  scanf("%d%d%d", &r, &c, &n);
  int x, y, ans = 0;
  for (int i = 1; i <= n; i++) {
    scanf("%d%d", &x, &y);
    a[x][y] = a[x][y + c] = 1;
    ++times;
    bool tf = 0;
    flag[Get((y - 1) * r + x)] = times;
    for (int j = 0; j <= 7; j++) {
      int xx = x + d[j][0], yy = y + d[j][1];
      if (!yy) yy = c + c;
      if (yy > c + c) yy = 1;
      if (a[xx][yy]) flag[Get((yy - 1) * r + xx)] = times;
    }
    for (int j = 0; j <= 7; j++) {
      int xx = x + d[j][0], yy = y + c + d[j][1];
      if (!yy) yy = c + c;
      if (yy > c + c) yy = 1;
      if (a[xx][yy])
        if (flag[Get((yy - 1) * r + xx)] == times) tf = 1;
    }
    if (!tf) {
      Do(x, y);
      Do(x, y + c);
      ans++;
    } else
      a[x][y] = a[x][y + c] = 0;
  }
  printf("%d\n", ans);
  return 0;
}
