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

import java.util.*;
import java.io.*;
import java.lang.Math.*;

public class Main {
    final int maxn = 3072;
    final int dx[] = {1, 1, 1, 0, 0, -1, -1, -1};
    final int dy[] = {1, 0, -1, 1, -1, 1, 0, -1};

    int n, m, k;
    Boolean a[][] = new Boolean[maxn][2 * maxn];
    int px[][] = new int[maxn][2 * maxn];
    int py[][] = new int[maxn][2 * maxn];
    ArrayList<Pair> v1 = new ArrayList<Pair>(), v2 = new ArrayList<Pair>();

    Boolean equal(Pair a, Pair b) {
        return a.x == b.x && a.y == b.y;
    }

    Pair get(int x, int y) {
        if (px[x][y] == x && py[x][y] == y) return new Pair(x, y);
        Pair o = get(px[x][y], py[x][y]);
        px[x][y] = o.x; py[x][y] = o.y;
        return o;
    }

    public void union(int x1, int y1, int x2, int y2) {
        Pair a = get(x1, y1); x1 = a.x; y1 = a.y;
        Pair b = get(x2, y2); x2 = b.x; y2 = b.y;
        if (equal(a, b)) return;

        if (Math.random() > 0.5) {
            int o;
            o = x1; x1 = x2; x2 = o;
            o = y1; y1 = y2; y2 = o;
        }
        px[x2][y2] = x1;
        py[x2][y2] = y1;
    }

    public void Run() {
        Scanner in = new Scanner(System.in);
        n = in.nextInt();
        m = in.nextInt();
        if (m == 1) {
            System.out.print(0);
            return;
        }
        k = in.nextInt();
        for (int i = 0; i <= n + 1; i++) for (int j = 0; j <= 2 * m + 1; j++) {
            a[i][j] = false;
            px[i][j] = i;
            py[i][j] = j;
        }


        int res = 0;
        for (int it = 0; it < k; it++) {
            int x, y;
            x = in.nextInt();
            y = in.nextInt();

            v1.clear();
            v2.clear();
            for (int i = 0; i < 8; i++) {
                if (a[x + dx[i]][y + dy[i]]) v1.add(get(x + dx[i], y + dy[i]));
                if (a[x + dx[i]][y + m + dy[i]]) v2.add(get(x + dx[i], y + m + dy[i]));
            }

            Boolean ok = true;
            for (int i = 0; i < v1.size(); i++) {
                for (int j = 0; j < v2.size(); j++) {
                    if (equal(v1.get(i), v2.get(j))) {
                        ok = false;
                    }
                }
            }

            if (ok) {
                res++;
                for (int i = 0; i < 8; i++) {
                    if (a[x + dx[i]][y + dy[i]]) union(x, y, x + dx[i], y + dy[i]);
                    if (a[x + dx[i]][y + m + dy[i]]) union(x, y + m, x + dx[i], y + m + dy[i]);
                }
                a[x][y] = true;
                a[x][y + m] = true;
            }
        }
        System.out.println(res);
    }

    public static void main(String[] args) {
        new Main().Run();
    }

    public class Pair {
        int x, y;

        Pair(int X, int Y) {
            x = X;
            y = Y;
        }
    }
}