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 R = 3010;
int n, m, fa[R * R * 2 + 2];
bool mark[R][R + R];
int vis[R * R * 2];
int idx = 0;
int dx[] = {0, 1, 0, -1, 1, 1, -1, -1}, dy[] = {1, 0, -1, 0, 1, -1, 1, -1};
int gf(int x) {
  if (fa[x] != x) fa[x] = gf(fa[x]);
  return fa[x];
}
int id(int x, int y) { return (x - 1) * m * 2 + y; }
bool ok(int x, int y) { return x >= 1 && x <= n && y >= 1 && y <= m * 2; }
int main() {
  int q, s = 0, x, y, i, j, L, R, xx, yy;
  bool gl, gr;
  scanf("%d%d%d", &n, &m, &q);
  for (i = 1; i <= n * m * 2; i++) fa[i] = i;
  while (q--) {
    gl = true;
    scanf("%d%d", &x, &y);
    if (!mark[x][y]) {
      idx++;
      for (i = 0; i < 8; i++) {
        xx = x + dx[i];
        yy = y + dy[i];
        if (yy < 1) yy = m * 2;
        if (yy > m * 2) yy = 1;
        if (ok(xx, yy) && mark[xx][yy]) vis[gf(id(xx, yy))] = idx;
      }
      y += m;
      for (i = 0; i < 8; i++) {
        xx = x + dx[i];
        yy = y + dy[i];
        if (yy < 1) yy = m * 2;
        if (yy > m * 2) yy = 1;
        if (ok(xx, yy) && mark[xx][yy])
          if (vis[gf(id(xx, yy))] == idx) gl = false;
      }
      if (!gl) continue;
      s++;
      y -= m;
      for (i = 0; i < 8; i++) {
        xx = x + dx[i];
        yy = y + dy[i];
        if (yy < 1) yy = m * 2;
        if (yy > m * 2) yy = 1;
        if (ok(xx, yy) && mark[xx][yy]) fa[gf(id(xx, yy))] = gf(id(x, y));
      }
      mark[x][y] = mark[x + n][y] = true;
      y += m;
      for (i = 0; i < 8; i++) {
        xx = x + dx[i];
        yy = y + dy[i];
        if (yy < 1) yy = m * 2;
        if (yy > m * 2) yy = 1;
        if (ok(xx, yy) && mark[xx][yy]) fa[gf(id(xx, yy))] = gf(id(x, y));
      }
    }
  }
  printf("%d\n", s);
}
