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 getint() {
  int x = 0, c = getchar();
  for (; c < 48 || c > 57; c = getchar())
    ;
  for (; c > 47 && c < 58; x = x * 10 + c - 48, c = getchar())
    ;
  return x;
}
const int dx[] = {1, 1, 1, -1, -1, -1, 0, 0},
          dy[] = {-1, 0, 1, -1, 0, 1, -1, 1};
int n, m, mm, q, p[3005 * 6005], s[3005 * 6005], ans;
bool del[3005][6005];
inline int find(int x) { return x == p[x] ? x : p[x] = find(p[x]); }
inline int hh(int x) {
  if (x < 1) {
    x += mm;
  }
  if (x > mm) {
    x -= mm;
  }
  return x;
}
inline void merge(int x, int y) {
  x = find(x), y = find(y);
  if (x == y) {
    return;
  }
  if (s[x] < s[y]) {
    swap(x, y);
  }
  p[y] = x;
  s[x] += s[x] == s[y];
}
int main() {
  scanf("%d%d%d", &n, &m, &q);
  if (m == 1) {
    puts("0");
    return 0;
  }
  mm = m << 1;
  for (int i = 1, g = n * mm; i <= g; ++i) {
    p[i] = i;
  }
  for (; q--;) {
    int x = getint(), y = getint();
    bool flag = 1;
    for (int i = 0; i < 8 && flag; ++i) {
      int fx = x + dx[i], fy = hh(y + dy[i]);
      if (fx < 1 || fx > n) {
        continue;
      }
      for (int j = 0; j < 8 && flag && del[fx][fy]; ++j) {
        int gx = x + dx[j], gy = hh(y + m + dy[j]);
        if (gx < 1 || gx > n) {
          continue;
        }
        if (del[gx][gy] &&
            find(((fx - 1) * m + fy)) == find(((gx - 1) * m + gy))) {
          flag = 0;
        }
      }
    }
    if (flag) {
      for (int i = 0; i < 8; ++i) {
        int fx = x + dx[i], fy = hh(y + dy[i]);
        if (fx < 1 || fx > n) {
          continue;
        }
        merge(((fx - 1) * m + fy), ((x - 1) * m + y));
        fy = hh(y + m + dy[i]);
        merge(((fx - 1) * m + fy), ((x - 1) * m + y + m));
      }
      del[x][y] = del[x][y + m] = 1;
      ++ans;
    }
  }
  cout << ans;
  return 0;
}
