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 <iostream>
#include <bits/stdc++.h>

using namespace std;
const int maxn = 3005;
const int hx[8] = {0,0,0,0,1,1,-1,-1};
const int hy[8] = {1,1,-1,-1,0,0,0,0};
bool dd[maxn][2*maxn];
int cha[maxn*maxn*2], rank[maxn*2*maxn];
int r, c, n;

int root(int x)
{
    if (cha[x] != x) return (cha[x] = root(cha[x]));
    else             return (x);
}

bool issameroot(int x, int y)
{
    return (root(x) == root(y));
}

void join(int x, int y)
{
    if (!issameroot(x,y))
    {
        int a = root(x);
        int b = root(y);
        if (rank[a] > rank[b]) cha[b] = a;
        else
        {
            cha[a] = b;
            if (rank[a] == rank[b]) rank[b]++;
        }
    }
}

int node(int a, int b)
{
    return ((a-1) * c + b);
}

bool connect(int x, int y, int u, int v)
{
    for (int i = 0; i < 8; ++i)
        for (int j = 0; j < 8; ++j)
    {
        int xx = x + hx[i];
        int yy = y + hy[i];
        int uu = u + hx[j];
        int vv = v + hy[j];
        if (xx == 0 || yy == 0 || uu == 0 || vv == 0 || xx == r + 1 || uu == r + 1 || yy == c + 1 || vv == c + 1 || dd[xx][yy] || dd[uu][vv]) continue;
        if (issameroot(node(xx,yy), node(uu,vv))) return true;
    }
    return false;
}

void update(int a, int b)
{
    dd[a][b] = false;
    for (int j = 0; j < 8; ++j)
    {
        int x = a+hx[j];
        int y = b+hy[j];
        if (x == 0 || y == 0 || x == r + 1 || y == c + 1 || dd[x][y] ) continue;
        join(node(a,b),node(x,y));
    }
}

int main()
{
    cin >> r >> c >> n;
    c <<= 1;
    for (int i = 1; i <= r; i++)
        for (int j = 1; j <= c; ++j)
    {
        cha[node(i,j)] = node(i,j);
        rank[node(i,j)] = 1;
        dd[i][j] = false;
    }
    int res = 0;
    for (int i = 0; i < n; ++i)
    {
        int a, b;
        cin >> a >> b;
        if (!connect(a,b,a,b+c/2))
        {
            update(a,b);
            update(a,b + c/2);
            res++;
        }
    }
    cout << res ;
    return 0;
}
