// see also: SRM 564 Div2 Hard KnightCircuit  / ナイトツアー
#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <complex>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <iomanip>
#include <assert.h>
#include <array>
#include <cstdio>
#include <cstring>
#include <random>
#include <functional>
#include <numeric>
#include <bitset>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)
#define all(c) (c).begin(), (c).end()
#define zero(a) memset(a, 0, sizeof a)
#define minus(a) memset(a, -1, sizeof a)
#define minimize(a, x) a = std::min(a, x)
#define maximize(a, x) a = std::max(a, x)

template<class T> constexpr bool in_range(T y, T x, T H, T W) { return -H<=y&&y<H&&-W<=x&&x<W; }

typedef long long ll;
int const inf = 1<<29;

int main() {

  int p, q; cin >> p >> q;
  int N; cin >> N;

  int ans = 0;
  ll g = __gcd(p, q);
  if(g > 0) { p /= g, q /= g; }
  rep(i, N) {
    ll x, y;
    cin >> x >> y;
    if (p == 0 && q == 0) {
      ans += x == 0 && y == 0;
    }
    else if(x % g == 0 && y % g == 0) {
      x /= g, y /= g;
      if(p % 2 && q % 2) {  // ichimatsu
        if((x + y) % 2 == 0) { ans ++; }
      }
      else {
        ans++;
      }
    }
  }
  cout << ans << endl;

  return 0;
}