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 n, m, K, i, j, k, tot, ans, x, y, now;
int id[3005][6005], fa[5000005];
int st[3000005], st_fa[3000005], top;
int get(int x) {
  if (fa[x] == x) return x;
  st[++top] = x;
  st_fa[top] = fa[x];
  fa[x] = get(fa[x]);
  return fa[x];
}
void Union(int x, int y) {
  if (!x || !y) return;
  if (x == y) return;
  x = get(x);
  y = get(y);
  st[++top] = x;
  st_fa[top] = x;
  fa[x] = y;
}
void Clear() {
  for (; top; --top) fa[st[top]] = st_fa[top];
}
int main() {
  scanf("%d%d%d", &n, &m, &K);
  tot = 2;
  for (i = 1; i <= K + K + K; ++i) fa[i] = i;
  for (; K; --K) {
    scanf("%d%d", &x, &y);
    top = 0;
    now = id[x][y] = ++tot;
    if (y == 1) Union(1, now);
    Union(now, id[x - 1][y]);
    Union(now, id[x + 1][y]);
    Union(now, id[x][y - 1]);
    Union(now, id[x][y + 1]);
    Union(now, id[x - 1][y - 1]);
    Union(now, id[x - 1][y + 1]);
    Union(now, id[x + 1][y - 1]);
    Union(now, id[x + 1][y + 1]);
    y += m;
    now = id[x][y] = ++tot;
    if (y == m + m) Union(2, m + m);
    Union(now, id[x - 1][y]);
    Union(now, id[x + 1][y]);
    Union(now, id[x][y - 1]);
    Union(now, id[x][y + 1]);
    Union(now, id[x - 1][y - 1]);
    Union(now, id[x - 1][y + 1]);
    Union(now, id[x + 1][y - 1]);
    Union(now, id[x + 1][y + 1]);
    if (get(1) == get(2)) {
      Clear();
      id[x][y] = 0;
      id[x][y - m] = 0;
      continue;
    }
    ++ans;
  }
  printf("%d\n", ans);
}
