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>
const int N = 3010;
int fa[N * N << 1];
std::stack<std::pair<int, int>> stack;
int find(int u) {
  if (fa[u] == u) {
    return u;
  }
  stack.push({u, fa[u]});
  return fa[u] = find(fa[u]);
}
void unite(int u, int v) {
  if (!~u || !~v) return;
  int _u = find(u), _v = find(v);
  if (_u == _v) {
    return;
  }
  stack.push({_u, fa[_u]});
  fa[_u] = _v;
}
int r, c, test;
int calc(int x, int y) {
  if (x <= 0 || x > r || y <= 0 || y > c << 1) return -1;
  return y * N + x;
}
int main() {
  scanf("%d%d%d", &r, &c, &test);
  int cnt = 0;
  while (test--) {
    int x, y;
    scanf("%d%d", &x, &y);
    while (!stack.empty()) {
      stack.pop();
    }
    int p1 = calc(x, y), p2 = calc(x, y + c);
    stack.push({p1, 0});
    stack.push({p2, 0});
    fa[p1] = p1;
    fa[p2] = p2;
    for (int i = -1; i <= 1; ++i) {
      for (int j = -1; j <= 1; ++j) {
        int moder = c << 1;
        int x1 = calc(x + i, ((y + j - 1) % moder + moder) % moder + 1);
        int x2 = calc(x + i, ((y + j + c - 1) % moder + moder) % moder + 1);
        if (~x1 && fa[x1]) {
          unite(p1, x1);
        }
        if (~x2 && fa[x2]) {
          unite(p2, x2);
        }
      }
    }
    if (find(calc(x, y)) == find(calc(x, y + c))) {
      while (!stack.empty()) {
        fa[stack.top().first] = stack.top().second;
        stack.pop();
      }
    } else {
      ++cnt;
    }
  }
  return printf("%d\n", cnt), 0;
}
