#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000
#define int long long

int gcd(int a, int b) {
	if (b > a) return gcd(b, a);
	else if (b == 0) return a;
	else return gcd(b, a % b);
}


signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
	int P, Q;
	cin >> P >> Q;
	if (P < Q) swap(P, Q);
	int X[100010], Y[100010];
	int N; cin >> N;
	rep(i, N) cin >> X[i] >> Y[i];

	int ans = 0;
	if (P) {
		int G = gcd(P, Q);
		P /= G, Q /= G;
		if ((P + Q) % 2) {
			rep(i, N) if (X[i] % G == 0 && Y[i] % G == 0) ans++;
		}
		else {
			rep(i, N) if (X[i] % G == 0 && Y[i] % G == 0) {
				X[i] /= G, Y[i] /= G;
				if ((X[i] + Y[i]) % 2 == 0) ans++;
			}
		}
	}
	else {
		rep(i, N) if (X[i] == 0 && Y[i] == 0) ans++;
	}
	cout << ans << endl;

    return 0;
}