#include<stdio.h>
#include<algorithm>
using namespace std;
int x[110000];
int y[110000];
int gcd(int a,int b){
	if(a<0)a=-a;
	if(b<0)b=-b;
	while(a){
		b%=a;int c=a;a=b;b=c;
	}
	return b;
}
int main(){
	int a,b;
	scanf("%d%d",&a,&b);
	int n;scanf("%d",&n);
	for(int i=0;i<n;i++)scanf("%d%d",x+i,y+i);
	int g=gcd(a,b);
	int t=(a+b)/g;
	int ret=0;
	if(g==0){
		for(int i=0;i<n;i++)if(x[i]==0&&y[i]==0)ret++;
		printf("%d\n",ret);
		return 0;
	}
	for(int i=0;i<n;i++){
		if(x[i]%g||y[i]%g)continue;
		int s=x[i]/g+y[i]/g;
		if(s<0)s=-s;
		if(t%2==0&&s%2!=0)continue;
		ret++;
	}
	printf("%d\n",ret);
}