#include <string>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <iostream>
#include <sstream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <limits>
#include <functional>
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i))
#define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))
#if defined(_MSC_VER) || __cplusplus > 199711L
#define aut(r,v) auto r = (v)
#else
#define aut(r,v) __typeof(v) r = (v)
#endif
#define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it)
#define all(o) (o).begin(), (o).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset(m,v,sizeof(m))
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
using namespace std;
typedef vector<int> vi; typedef pair<int,int> pii; typedef vector<pair<int,int> > vpii; typedef long long ll;
template<typename T, typename U> inline void amin(T &x, U y) { if(y < x) x = y; }
template<typename T, typename U> inline void amax(T &x, U y) { if(x < y) x = y; }

template<typename T>T gcd(T x, T y) { if(y == 0)return x; else return gcd(y, x%y); }

int main() {
	int P; int Q;
	while(~scanf("%d%d", &P, &Q)) {
		P = abs(P), Q = abs(Q);
		int g = max(1, gcd(P, Q));
		P /= g, Q /= g;
		int N;
		scanf("%d", &N);
		int ans = 0;
		rep(i, N) {
			int X; int Y;
			scanf("%d%d", &X, &Y);
			X = abs(X), Y = abs(Y);
			bool ok = true;
			ok &= X % g == 0 && Y % g == 0;
			X /= g, Y /= g;
			if(P == 0 && Q == 0) {
				ok &= X == 0 && Y == 0;
			} else if((P + Q) % 2 == 0) {
				ok &= (X + Y) % 2 == 0;
			} else {
			}
			ans += ok;
		}
		printf("%d\n", ans);
	}
	return 0;
}