import java.util.*;

public class Main {
	static long gcd(long a,long b){
		return b == 0 ? a : gcd(b, a%b);
	}
	static long lcm(long a, long b){
		return a*b/gcd(a, b);
	}
	static int[] dx = {1,0,-1,0};
	static int[] dy = {0,1,0,-1};
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		
		long p = sc.nextLong();
		long q = sc.nextLong();
		int n = sc.nextInt();
		if(p>q){
			long tmp = p;
			p = q;
			q = tmp;
		}
		int[] x = new int[n];
		int[] y = new int[n];
		for(int i=0;i<n;i++){
			x[i] = sc.nextInt();
			y[i] = sc.nextInt();
		}
		int ret = 0;
		if(q>0){
			long g = gcd(p, q);
			if(((p/g)+(q/g))%2==1){
				for(int i=0;i<n;i++){
					if(x[i]%g==0 && y[i]%g==0) ret++;
				}
			}else{
				for(int i=0;i<n;i++){
					if(x[i]%g==0 && y[i]%g==0 && Math.abs(x[i]/g+y[i]/g)%2==0){
						ret++;
					}
				}
			}
		}else{
			for(int i=0;i<n;i++) if(x[i]==0 && y[i]==0) ret++;
		}
		System.out.println(ret);
	}
}