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 BufferSize = 1 << 16;
char buffer[BufferSize], *Head, *Tail;
inline char Getchar() {
  if (Head == Tail) {
    int l = fread(buffer, 1, BufferSize, stdin);
    Tail = (Head = buffer) + l;
  }
  return *Head++;
}
int read() {
  int x = 0, f = 1;
  char c = getchar();
  while (!isdigit(c)) {
    if (c == '-') f = -1;
    c = getchar();
  }
  while (isdigit(c)) {
    x = x * 10 + c - '0';
    c = getchar();
  }
  return x * f;
}
int r, c, n;
bool has[3010][3010];
int fa[9000010];
int findset(int x) { return x == fa[x] ? x : fa[x] = findset(fa[x]); }
int main() {
  r = read();
  c = read();
  n = read();
  for (int i = 0; i < r * c; i++) fa[i] = i;
  int ans = 0;
  for (int i = 1; i <= n; i++) {
    int x = read() - 1, y = read() - 1, a = x * r + y;
    int ns[10], tp[10], cnt = 0;
    if (x) {
      if (has[x - 1][(y + 1) % c])
        ns[++cnt] = (x - 1) * r + (y + 1) % c, tp[cnt] = 0;
      if (has[x - 1][(y - 1 + c) % c])
        ns[++cnt] = (x - 1) * r + (y - 1 + c) % c, tp[cnt] = 1;
    }
    if (has[x][(y + 1) % c]) ns[++cnt] = x * r + (y + 1) % c, tp[cnt] = 0;
    if (has[x][(y - 1 + c) % c])
      ns[++cnt] = x * r + (y - 1 + c) % c, tp[cnt] = 1;
    if (x < r - 1) {
      if (has[x + 1][(y + 1) % c])
        ns[++cnt] = (x + 1) * r + (y + 1) % c, tp[cnt] = 0;
      if (has[x + 1][(y - 1 + c) % c])
        ns[++cnt] = (x + 1) * r + (y - 1 + c) % c, tp[cnt] = 1;
    }
    bool ok = 1;
    for (int i = 1; i <= cnt; i++) {
      for (int j = 1; j <= cnt; j++)
        if (tp[i] != tp[j]) {
          int u = findset(ns[i]), v = findset(ns[j]);
          if (u == v) {
            ok = 0;
            break;
          }
        }
      if (!ok) break;
    }
    if (ok) {
      has[x][y] = 1;
      ans++;
      for (int i = 1; i <= cnt; i++)
        for (int j = 1; j <= cnt; j++)
          if (i != j) {
            int u = findset(ns[i]), v = findset(ns[j]);
            if (u != v) fa[v] = u;
          }
      if (cnt) {
        int u = findset(ns[1]), v = findset(a);
        if (u != v) fa[v] = u;
      }
    }
  }
  printf("%d\n", ans);
  return 0;
}
