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>
int n, m, M;
int id[3000][6000];
int st[600001];
int u[600001], uid;
int mm[8][2] = {{0, 1}, {0, -1}, {1, 0},  {-1, 0},
                {1, 1}, {1, -1}, {-1, 1}, {-1, -1}};
int find(int x) { return x == st[x] ? x : st[x] = find(st[x]); }
inline void Union(int a, int b) {
  if (a != b) st[a] = b;
}
inline int check(int x, int y) {
  int j, dx, dy;
  uid++;
  for (j = 0; j < 8; j++) {
    dx = x + mm[j][0];
    dy = (y + mm[j][1] + M) % M;
    if (dx < 0 || dx >= n || !id[dx][dy]) continue;
    u[find(id[dx][dy])] = uid;
  }
  for (j = 0; j < 8; j++) {
    dx = x + mm[j][0];
    dy = (y + mm[j][1] + m + M) % M;
    if (dx < 0 || dx >= n || !id[dx][dy]) continue;
    if (u[find(id[dx][dy])] == uid) {
      return 0;
    }
  }
  return 1;
}
int main() {
  int r, i, j, x, y, s, dx, dy;
  scanf("%d %d %d", &n, &m, &r);
  if (m == 1) {
    puts("0");
    return 0;
  }
  M = m * 2;
  s = 0;
  for (i = 1; i <= r * 2; i++) {
    st[i] = i;
  }
  for (i = 1; i <= r; i++) {
    scanf("%d %d", &x, &y);
    x--;
    y--;
    if (check(x, y)) {
      id[x][y] = i;
      id[x][y + m] = i + r;
      for (int f = 0; f < 2; f++) {
        for (j = 0; j < 8; j++) {
          dx = x + mm[j][0];
          dy = (y + mm[j][1] + m * f + M) % M;
          if (dx < 0 || dx >= n || !id[dx][dy]) continue;
          Union(find(i + r * f), find(id[dx][dy]));
        }
      }
      s++;
    }
  }
  printf("%d\n", s);
  return 0;
}
