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);
	}
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		long p = sc.nextLong();
		long q = sc.nextLong();
		int n = sc.nextInt();
		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();
		}
		if(gcd(p, q)==1 && (p%2==0 || q%2==0)){
			System.out.println(n);
		}else if(gcd(p, q)==1){
			int ans = 0;
			for(int i=0;i<n;i++){
				if( Math.abs(x[i]-y[i])%2!=0) ans++;
			}
			System.out.println(ans);
		}else if(p==0&&q==0){
			int ans = 0;
			for(int i=0;i<n;i++){
				if( x[i]==0&&y[i]==0) ans++;
			}
			System.out.println(ans);
		}else if(p==0){
			int ans = 0;
			for(int i=0;i<n;i++){
				if( y[i]%q==0 && x[i]%q==0) ans++;
			}
			System.out.println(ans);
		}else if(q==0){
			int ans = 0;
			for(int i=0;i<n;i++){
				if( y[i]%p==0 && x[i]%p==0) ans++;
			}
			System.out.println(ans);
		}else{
			int ans =0;
			long sa = gcd(p, q);
			for(int i=0;i<n;i++){
				if( (x[i]%sa==0 || y[i]%sa==0) && Math.abs(x[i]-y[i])%(sa*2)==0) ans++;
			}
			System.out.println(ans);
		}
	} 
}