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 father[18000010], nRow, nCol, S, T;
bool col[3010][3010 * 2];
int movex[] = {1, 1, 1, 0, 0, -1, -1, -1};
int movey[] = {-1, 0, 1, 1, -1, -1, 0, 1};
int Find(int p, int *father) {
  if (father[p] != p) father[p] = Find(father[p], father);
  return father[p];
}
void read() {
  scanf("%d %d", &nRow, &nCol);
  nCol *= 2;
  for (int i = 1; i <= nRow * nCol; ++i) father[i] = i;
  S = nRow * nCol + 1, T = nRow * nCol + 2;
  father[S] = S, father[T] = T;
}
bool check(int x1, int y1, int x2, int y2) {
  static int fa[18000010], e[3010][2];
  col[x1][y1] = col[x2][y2] = 1;
  int tot = 0;
  int pa = Find((x1 - 1) * nCol + y1, father),
      pb = Find((x2 - 1) * nCol + y2, father);
  fa[Find(pa, father)] = father[pa], fa[Find(pb, father)] = father[pb];
  fa[Find(S, father)] = father[S], fa[Find(T, father)] = father[T];
  for (int j = 0, x, y; j < 8; ++j) {
    x = x1 + movex[j], y = y1 + movey[j];
    if (y == 0) ++tot, e[tot][0] = father[S], e[tot][1] = pa;
    if (y == nCol + 1) ++tot, e[tot][0] = father[T], e[tot][1] = pa;
    if (x >= 1 && x <= nRow && y >= 1 && y <= nCol && col[x][y]) {
      int p = Find((x - 1) * nCol + y, father);
      fa[p] = p, ++tot, e[tot][0] = p, e[tot][1] = pa;
    }
    x = x2 + movex[j], y = y2 + movey[j];
    if (y == 0) ++tot, e[tot][0] = father[S], e[tot][1] = pb;
    if (y == nCol + 1) ++tot, e[tot][0] = father[T], e[tot][1] = pb;
    if (x >= 1 && x <= nRow && y >= 1 && y <= nCol && col[x][y]) {
      int p = Find((x - 1) * nCol + y, father);
      fa[p] = p, ++tot, e[tot][0] = p, e[tot][1] = pb;
    }
  }
  int a = father[S], b = father[T];
  for (int i = 1; i <= tot; ++i) {
    if (father[e[i][0]] != e[i][0] || father[e[i][1]] != e[i][1] || !e[i][0] ||
        !e[i][1])
      while (1)
        ;
    fa[Find(e[i][0], fa)] = Find(e[i][1], fa);
  }
  col[x1][y1] = col[x2][y2] = 0;
  return Find(father[S], fa) != Find(father[T], fa);
}
void work(int a, int b) {
  int pa = Find((a - 1) * nCol + b, father);
  for (int j = 0; j < 8; ++j) {
    int x = a + movex[j], y = b + movey[j];
    if (x < 1 || x > nRow) continue;
    if (y == 0) father[Find(pa, father)] = Find(S, father);
    if (y == nCol + 1) father[Find(pa, father)] = Find(T, father);
    if (x >= 1 && x <= nRow && y >= 1 && y <= nCol && col[x][y])
      father[Find((x - 1) * nCol + y, father)] = Find(pa, father);
  }
}
void Query() {
  int cnt = 0, m;
  scanf("%d", &m);
  for (int i = 1, a, b; i <= m; ++i) {
    scanf("%d %d", &a, &b);
    if (check(a, b, a, b + nCol / 2))
      ++cnt, work(a, b), work(a, b + nCol / 2), col[a][b] = 1,
                                                col[a][b + nCol / 2] = 1;
  }
  printf("%d\n", cnt);
}
int main() {
  read();
  Query();
  return 0;
}
