// yukicoder: No.321 (P,Q)-サンタと街の子供たち
// 2019.7.28 bal4u

#include <stdio.h>

#if 1
#define gc() getchar_unlocked()
#else
#define gc() getchar()
#endif

int in()   // 整数の入力（負数対応）
{
	int n = 0, c = gc();
	if (c == '-') {	c = gc();
		do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
		return -n;
	}
	do n = 10*n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

int gcd(int a, int b) {
	int r;
	while (b != 0) r = a % b, a = b, b = r;
	return a;
}

int main()
{
	int P, Q, N, x, y, g, ans;

	ans = 0;
	P = in(), Q = in(), N = in();
	if (P == 0 && Q == 0) while (N--) x = in(), y = in(), ans += ((x | y) == 0);
	else if (P == 0) {
		if (Q == 1) ans = N;
		else while (N--) x = in(), y = in(), ans += (x % Q == 0) && (y % Q == 0);
	} else if (Q == 0) {
		if (P == 1) ans = N;
		else while (N--) x = in(), y = in(), ans += (x % P == 0) && (y % P == 0);
	} else {
		g = gcd(P, Q), P /= g, Q /= g;
		if ((P & 1) && (Q & 1)) while (N--) {
			x = in(), y = in(), ans += (x % g == 0 && y % g == 0 && ((x/g+y/g) & 1) == 0);
		} else if (g == 1) ans = N;
		else while (N--) {
			x = in(), y = in(), ans += (x % g == 0 && y % g == 0);
		}
	}
	printf("%d\n", ans);
	return 0;
}