#include <bits/stdc++.h>
using namespace std;
#define repl(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repl(i,0,n)
#define mp(a,b) make_pair((a),(b))
#define pb(a) push_back((a))
#define all(x) (x).begin(),(x).end()
#define uniq(x) sort(all(x)),(x).erase(unique(all(x)),end(x))
#define fi first
#define se second
#define dbg(x) cout<<#x" = "<<((x))<<endl
template<class T,class U> ostream& operator<<(ostream& o, const pair<T,U> &p){o<<"("<<p.fi<<","<<p.se<<")";return o;}
template<class T> ostream& operator<<(ostream& o, const vector<T> &v){o<<"[";for(T t:v){o<<t<<",";}o<<"]";return o;}

#define INF 2147483600

// a*x + b*y = gcd(a, b)
int extgcd(int a, int b, int& x, int& y){
  int d=a;
  if(b!=0){
    d=extgcd(b, a%b, y, x);
    y-=(a/b)*x;
  } else {
    x=1; y=0;
  }
  return d;
}

int main(){
  int p,q,n;
  cin>>p>>q>>n;
  vector<int> x(n), y(n);
  rep(i,n) cin>>x[i]>>y[i];

  int ans=0;
  if(p==0 && q==0){
    rep(i,n) if(x[i]==0 && y[i]==0) ans++;
  }
  else if(p==0 || q==0){
    p = q = max(p,q);
    rep(i,n) if(x[i]%q==0 && y[i]%q==0) ans++;
  }
  else{
    int g = __gcd(p,q);
    p /= g; q /= g;
    rep(i,n){
      if(x[i]%g!=0 || y[i]%g!=0) continue;
      if(p%2==0 || q%2==0) ans++;
      else {
        x[i] /= g; if(x[i]<0) x[i] *= -1;
        y[i] /= g; if(y[i]<0) y[i] *= -1;
        if(x[i]%2 == y[i]%2) ans++;
      }
    }
  }

  cout << ans << endl;

  return 0;
}