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, k, ans, top, u[25], v[25], fa[18000010], sz[18000010],
    mark[3010][6010], xx[8] = {1, 1, 1, -1, -1, -1, 0, 0},
                      yy[8] = {1, -1, 0, 1, -1, 0, 1, -1};
int f(int x, int y) { return 2 * (x - 1) * m + y; }
int find(int x) { return x == fa[x] ? x : find(fa[x]); }
void unite(int x, int y) {
  if (x == y) return;
  if (sz[x] > sz[y]) swap(x, y);
  fa[x] = y;
  sz[y] += sz[x];
  u[++top] = x;
  v[top] = y;
}
void add(int x, int y) {
  mark[x][y] = 1;
  for (int i = 0; i < 8; ++i) {
    int newx = x + xx[i], newy = y + yy[i];
    if (newy < 1) newy = 2 * m;
    if (newy > 2 * m) newy = 1;
    if (mark[newx][newy]) unite(find(f(x, y)), find(f(newx, newy)));
  }
}
int main() {
  scanf("%d%d%d", &n, &m, &k);
  for (int i = 1; i <= 2 * n * m; ++i) fa[i] = i, sz[i] = 1;
  for (int i = 1, x, y; i <= k; ++i) {
    top = 0;
    scanf("%d%d", &x, &y);
    add(x, y);
    add(x, y + m);
    if (find(f(x, y)) == find(f(x, y + m))) {
      mark[x][y] = mark[x][y + m] = 0;
      while (top) {
        fa[u[top]] = u[top];
        sz[v[top]] -= sz[u[top]];
        --top;
      }
    } else
      ++ans;
  }
  printf("%d\n", ans);
}
