/* No.321 (P,Q)-サンタと街の子供たち */

#include <iostream>
#include <vector>

using namespace std;

typedef long long int Int;

Int gcd(Int m, Int n){
	if((m == 0) || (n == 0)) return 0;
	while(m != n){
		if(m > n) m -= n; else n -= m;
	}
	return m;
}

int main(){
	// 読み込み
	Int P, Q, N;
	cin >> P >> Q >> N;
	vector<Int> X, Y;
	for(Int i = 0; i < N; ++i){
		Int x, y;
		cin >> x >> y;
		X.push_back(x);
		Y.push_back(y);
	}
	// 計算
	if((P == 0) && (Q == 0)){
		cout << "0\n";
		return 0;
	}
	if((P == 0) && (Q != 0)) P = Q;
	if((P != 0) && (Q == 0)) Q = P;
	Int R = gcd(P, Q);
	Int sum = 0;
	for(Int i = 0; i < N; ++i){
		if((X[i] % R == 0) && (Y[i] % R == 0)){
			Int x = abs(X[i] / R), y = abs(Y[i] / R);
			if(x == y){
				++sum;
			}else{
				if((P % 2 == 0) && (Q % 2 == 1)) ++sum;
				if((P % 2 == 1) && (Q % 2 == 0)) ++sum;
			}
		}
	}
	cout << sum << "\n";
}