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, ans;
int f[18000000];
int g[18000000];
bitset<18000000> v;
int getfa(int x) { return f[x] == x ? x : f[x] = getfa(f[x]); }
int id(int x, int y) { return (y - 1) * n + x - 1; }
bool check(int x, int y) { return x > 0 && x <= n && y <= m * 2 && y > 0; }
int main() {
  int Q, i, j, x, y, t, tx, ty;
  scanf("%d%d%d", &n, &m, &Q);
  if (m == 1) return puts("0"), 0;
  for (i = 0; i < n * m * 2; i++) f[i] = i;
  for (t = 1; t <= Q; t++) {
    scanf("%d%d", &x, &y);
    if (v[id(x, y)]) {
      ans++;
      continue;
    }
    for (i = -(x > 1); i <= (x < n); i++)
      for (j = -1; j <= 1; j++)
        if (i || j) {
          tx = x + i, ty = y + j;
          if (ty < 1) ty += m + m;
          if (v[id(tx, ty)]) g[getfa(id(tx, ty))] = t;
        }
    for (i = -(x > 1); i <= (x < n); i++)
      for (j = -1; j <= 1; j++)
        if (i || j) {
          tx = x + i, ty = y + j + m;
          if (ty > m + m) ty -= m + m;
          if (v[id(tx, ty)])
            if (g[getfa(id(tx, ty))] == t) goto fail;
        }
    v[id(x, y)] = v[id(x, y + m)] = 1;
    for (i = -(x > 1); i <= (x < n); i++)
      for (j = -1; j <= 1; j++)
        if (i || j) {
          tx = x + i, ty = y + j;
          if (ty < 1) ty += m + m;
          if (v[id(tx, ty)]) f[getfa(id(tx, ty))] = id(x, y);
        }
    for (i = -(x > 1); i <= (x < n); i++)
      for (j = -1; j <= 1; j++)
        if (i || j) {
          tx = x + i, ty = y + j + m;
          if (ty > m + m) ty -= m + m;
          if (v[id(tx, ty)]) f[getfa(id(tx, ty))] = id(x, y + m);
        }
    ans++;
  fail:;
  }
  printf("%d\n", ans);
}
