#include <bits/stdc++.h>

#define fst(t) std::get<0>(t)
#define snd(t) std::get<1>(t)
#define thd(t) std::get<2>(t)
#define unless(p) if(!(p))
#define until(p) while(!(p))

using ll = std::int64_t;

ll P, Q, N;

template <typename T>
std::tuple<T, T, T> extgcd(T a, T b){
    T s1 = 1, t1 = 0, s2 = 0, t2 = 1;
    while(b != 0){
        std::tie(s1, t1, s2, t2) = std::make_tuple(s2, t2, s1 - (a / b) * s2, t1 - (a / b) * t2);
        std::tie(a, b) = std::make_tuple(b, a % b);
    }
    return std::make_tuple(s1, t1, a);
}

bool f(ll p, ll q, ll x, ll y){
    if(p == 0 && q == 0){
        return x == 0 && y == 0;
    }

    ll s, t, g;
    std::tie(s, t, g) = extgcd(p, q);

    if(x % g != 0 || y % g != 0){
        return false;
    }

    ll s1 = (x / g) * s, t1 = (x / g) * t,
        s2 = (y / g) * t, t2 = (y / g) * s;

    if((p / g) % 2 != (q / g) % 2){
        return true;
    }

    return !((s1 + s2) & 1) && !((t1 + t2) & 1);
}

int main(){
    std::cin.tie(nullptr);
    std::ios::sync_with_stdio(false);

    std::cin >> P >> Q >> N;

    int cnt = 0;
    
    for(int i=0;i<N;++i){
        ll X, Y;
        std::cin >> X >> Y;

        if(f(P, Q, X, Y)){
            cnt += 1;
        }
    }

    std::cout << cnt << std::endl;
}