#include <iostream>
#include <vector>
using namespace std;
int gcd(int a, int b){
	if (b == 0){
		return a;
	} else {
		return gcd(b, a % b);
	}
} 
int main(){
	int P, Q;
	cin >> P >> Q;
	int N;
	cin >> N;
	vector<int> X(N), Y(N);
	for (int i = 0; i < N; i++){
		cin >> X[i] >> Y[i];
	}
	if (P == 0 && Q == 0){
		int ans = 0;
		for (int i = 0; i < N; i++){
			if (X[i] == 0 && Y[i] == 0){
				ans++;
			}
		}
		cout << ans << endl;
	} else {
		int g = gcd(P, Q);
		bool even = false;
		if ((P / g + Q / g) % 2 == 0){
			even = true;
		}
		int ans = 0;
		for (int i = 0; i < N; i++){
			if (X[i] % g == 0 && Y[i] % g == 0 && !(even && (X[i] / g + Y[i] / g) % 2 != 0)){
				ans++;
			}
		}
		cout << ans << endl;
	}
	return 0;
}