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 gint() {
  char c;
  int f = 1;
  while (c = getchar(), c < 48 || c > 57)
    if (c == '-') f = -1;
  int x = 0;
  for (; c > 47 && c < 58; c = getchar()) {
    x = x * 10 + c - 48;
  }
  return x * f;
}
struct hash {
  int a[103005 << 2], b[103005 << 2], next[103005 << 2];
  int head[65535 + 1], tot;
  inline int& operator[](int x) {
    int p = x & 65535;
    for (int i = head[p]; i; i = next[i])
      if (a[i] == x) return b[i];
    a[++tot] = x, b[tot] = x;
    next[tot] = head[p], head[p] = tot;
    return b[tot];
  }
} f;
int r, c, n, s, t, ans;
int find(int x) { return x == f[x] ? x : f[x] = find(f[x]); }
int main() {
  r = gint(), c = gint();
  s = (r + 1) * 10000 + c, t = s + 1;
  for (int i = 0; i < c; ++i) f[i] = s, f[r * 10000 + i] = t;
  n = gint();
  for (int i = 1, x, y; i <= n; ++i) {
    x = gint(), y = gint();
    int u1 = find(x * 10000 + (y % c));
    int u2 = find(x * 10000 + y - 1);
    int u3 = find((x - 1) * 10000 + (y % c));
    int u4 = find((x - 1) * 10000 + y - 1);
    int us = find(s), ut = find(t);
    bool flag1 = u1 == us || u2 == us || u3 == us || u4 == us;
    bool flag2 = u1 == ut || u2 == ut || u3 == ut || u4 == ut;
    if (flag1 && flag2) continue;
    ++ans, f[u2] = f[u3] = f[u4] = u1;
  }
  return printf("%d\n", ans), 0;
}
