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;
typedef long long ll;
inline void read(ll& x)
{
	static char c;
	register ll f=1;
	while(!isdigit(c=getchar()))
	{
		if(c=='-')f=-1;
	}
	x=c&15;
	while(isdigit(c=getchar()))
	{
		x*=10;x+=c&15;
	}
	x*=f;
}
inline void read(int& x)
{
	static char c;
	register int f=1;
	while(!isdigit(c=getchar()))
	{
		if(c=='-')f=-1;
	}
	x=c&15;
	while(isdigit(c=getchar()))
	{
		x*=10;x+=c&15;
	}
	x*=f;
}
inline void write(ll x)
{
	if(x<0)putchar('-'),x=-x;
	if(x>9)write(x/10);
	putchar('0'|x%10);
}
int r,c,n;
pair<int,int>st[3002][6002];
bool u[3002][6002];
pair<int,int>fa(const pair<int,int>& a)
{
	if(st[a.first][a.second]==a)return a;
	return st[a.first][a.second]=fa(st[a.first][a.second]);
}
void ad(const pair<int,int>& a,const pair<int,int>& b)
{
	st[fa(b).first][fa(b).second]=fa(a);
}
int cg1(const int& y)
{
	if(y>c<<1)return y-(c<<1);
	if(y<1)return y+(c<<1);
	return y;
}
int cg2(const int& y)
{
	if(y>c<<1)return y-(c<<1);
	if(y<1)return y+(c<<1);
	return y;
}
bool hf(const int& x)
{
	if(x<=1||x>r)return 0;
	return 1;
}
int dx[8]={-1,0,1,-1,1,-1,0,1},dy[8]={-1,-1,-1,0,0,1,1,1};
int main()
{
//	freopen("wa.in","r",stdin);
//	freopen("wa.out","w",stdout); 
	read(r),read(c),read(n);
	int x,y;
	if(c==1)
	{
		write(0);return 0;
	}
	int cnt=0;
	for(int i=1;i<=r;i++)
	{
		for(int j=1;j<=c<<1;j++)
		{
			st[i][j]=pair<int,int>(i,j);
		}
	}
	for(int i=1;i<=n;i++)
	{
		read(x),read(y);
//		if(u[x][y])continue;
		for(int i=0;i<8;i++)
		{
			for(int j=0;j<8;j++)
			{
				if(hf(x+dx[i])&&hf[x+dx[j]]&&u[x+dx[i]][cg1(y+dy[i])]&&u[x+dx[i]][cg2(y+c+dy[i])]&&
				(fa(pair<int,int>(x+dx[i],cg1(y+dy[i])))==fa(pair<int,int>(x+dx[j],cg2(y+c+dy[j])))))
				{
					goto out;
				}
			}	
		}
		u[x][y]=u[x][y+c]=1;
		for(int i=0;i<8;i++)
		{
			if(!hf(x+dx[i]))continue;
			if(u[x+dx[i]][cg1(y+dy[i])])
			ad(pair<int,int>(x+dx[i],cg1(y+dy[i])),pair<int,int>(x,y));
			if(u[x+dx[i]][cg2(y+c+dy[i])])
			ad(pair<int,int>(x+dx[i],cg2(y+c+dy[i])),pair<int,int>(x,y+c));
		}
		cnt++;
		out:;
	}
	write(cnt);
	return 0;
}