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;
inline long long read() {
  long long sum = 0, f = 0;
  char c = getchar();
  while (!isdigit(c)) f |= (c == '-'), c = getchar();
  while (isdigit(c)) sum = (sum << 1) + (sum << 3) + (c ^ 48), c = getchar();
  return f ? -sum : sum;
}
const long long N = 5010;
long long n, m, q, ans, vis[N * N], fa[N * N], tmp1[N], tmp2[N];
long long fx[N][2] = {{1, 1},  {1, 0},  {1, -1}, {0, 1},
                      {0, -1}, {-1, 1}, {-1, 0}, {-1, -1}};
inline long long code(long long x, long long y) { return m * (x - 1) + y; }
inline bool ok(long long x, long long y) {
  y = (y == 0) ? m : (y == m + 1) ? 1 : y;
  return x >= 1 && x <= n && y >= 1 && y <= m;
}
long long getfa(long long x) { return fa[x] == x ? x : fa[x] = getfa(fa[x]); }
inline void _merge(long long x, long long y) { fa[getfa(x)] = getfa(y); }
inline void merge(long long x, long long y) {
  vis[code(x, y)] = 1;
  for (register long long i = (0); i <= (7); i++) {
    long long xx = x + fx[i][0], yy = y + fx[i][1];
    if (ok(xx, yy) && vis[code(xx, yy)]) _merge(code(x, y), code(xx, yy));
  }
}
inline void copy(long long *a, long long x, long long y) {
  for (register long long i = (0); i <= (7); i++)
    a[i] = fa[code(x + fx[i][0], y + fx[i][1])];
}
inline void recopy(long long *a, long long x, long long y) {
  vis[code(x, y)] = 0;
  for (register long long i = (0); i <= (7); i++)
    fa[code(x + fx[i][0], y + fx[i][1])] = a[i];
}
signed main() {
  n = read(), m = read() << 1, q = read(), ans = 0;
  for (register long long i = (1); i <= (n); i++)
    for (register long long j = (1); j <= (m); j++) fa[code(i, j)] = code(i, j);
  for (register long long i = (1); i <= (q); i++) {
    long long x = read(), y = read();
    copy(tmp1, x, y), copy(tmp2, x, y + (m >> 1));
    merge(x, y), merge(x, y + (m >> 1));
    if (getfa(code(x, y)) == getfa(code(x, y + (m >> 1))))
      recopy(tmp1, x, y), recopy(tmp2, x, y + (m >> 1));
    else
      ans++;
  }
  printf("%lld\n", ans);
}
