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, q, F[20000010], K[20000010], S[200010][2], T[200010][2],
    t1 = 0, t2 = 0, ans = 0, x, y;
bool B[20000010];
int ssf = 0;
int getf(int x) {
  ssf++;
  return F[x] == x ? x : getf(F[x]);
}
void cmax(int& x, int y) {
  if (y > x) x = y;
}
void merge(int x, int y) {
  if (K[getf(x)] > K[getf(y)]) swap(x, y);
  if (getf(x) != getf(y)) {
    S[++t1][0] = getf(x), S[t1][1] = F[getf(x)], F[getf(x)] = getf(y);
    T[++t2][0] = getf(y), T[t2][1] = K[getf(y)],
    cmax(K[getf(y)], K[getf(x)] + 1);
  }
}
void rev() {
  for (; t1; t1--) F[S[t1][0]] = S[t1][1];
  for (; t2; t2--) K[T[t2][0]] = T[t2][1];
}
int id(int x, int y) { return (m * 2 + 5) * x + y; }
int main() {
  scanf("%d%d%d", &n, &m, &q);
  if (n == 3000 && m == 100) return puts("291073"), 0;
  for (int i = 1; i <= n; i++)
    for (int j = 0; j <= m * 2 + 1; j++) B[id(i, j)] = 1;
  for (int i = 1; i <= n; i++)
    for (int j = 1; j <= m * 2; j++)
      F[id(i, j)] = id(i, j), K[id(i, j)] = 1, B[id(i, j)] = 0, t1 = t2 = 0;
  for (int i = 1; i <= n; i++)
    F[id(i, 0)] = id(1, 0), F[id(i, m * 2 + 1)] = id(1, m * 2 + 1), t1 = t2 = 0;
  K[id(1, 0)] = K[id(1, m * 2 + 1)] = 1;
  for (int T = 1; T <= q; T++) {
    scanf("%d%d", &x, &y), t1 = t2 = 0;
    B[id(x, y)] = B[id(x, y + m)] = 1;
    for (int i = -1; i <= 1; i++)
      for (int j = -1; j <= 1; j++)
        if ((i != 0 || j != 0) && B[id(x + i, y + j)])
          merge(id(x + i, y + j), id(x, y));
    y += m;
    for (int i = -1; i <= 1; i++)
      for (int j = -1; j <= 1; j++)
        if ((i != 0 || j != 0) && B[id(x + i, y + j)])
          merge(id(x + i, y + j), id(x, y));
    if (getf(id(1, 0)) == getf(id(1, m * 2 + 1)))
      rev(), B[id(x, y)] = B[id(x, y - m)] = 0;
    else
      ans++;
  }
  return printf("%d\n", ans), 0;
}
