/* -*- coding: utf-8 -*-
 *
 * 321.cc: No.321 (P,Q)-繧ｵ繝ｳ繧ｿ縺ｨ陦励・蟄蝉ｾ帙◆縺｡ - yukicoder
 */

#include<cstdio>
#include<algorithm>
#include<numeric>
 
using namespace std;

/* constant */

const int MAX_N = 100000;

/* typedef */

/* global variables */

int xs[MAX_N], ys[MAX_N];

/* subroutines */

/* main */

int main() {
  int p, q, n;
  scanf("%d%d%d", &p, &q, &n);
  for (int i = 0; i < n; i++) scanf("%d%d", xs + i, ys + i);

  int cnt = 0;

  if (p == 0 && q == 0) {
    for (int i = 0; i < n; i++)
      if (xs[i] == 0 && ys[i] == 0) cnt++;
  }
  else if (p == 0 || q == 0) {
    int d = max(p, q);
    for (int i = 0; i < n; i++)
      if (xs[i] % d == 0 && ys[i] % d == 0) cnt++;
  }
  else { // p > 0 && q > 0
    int g = gcd(p, q);
    p /= g, q /= g;
    bool f = ((p + q) & 1);
    for (int i = 0; i < n; i++)
      if (xs[i] % g == 0 && ys[i] % g == 0 &&
	  (abs(xs[i]) == abs(ys[i]) || f)) cnt++;
  }

  printf("%d\n", cnt);
  
  return 0;
}