#include <bits/stdc++.h>

#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define RFOR(i, a, b) for (int i = (b)-1; i >= (a); i--)
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
#define rrep(i, n) for (int i = (n)-1; i >= 0; i--)

#define pb push_back
#define mp make_pair
#define fst first
#define snd second
#define show(x) cout << #x << " = " << x << endl
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define pii pair<int, int>
#define vi vector<int>

using namespace std;
template <class S, class T>
ostream& operator<<(ostream& o, const pair<S, T>& p)
{
    return o << "(" << p.first << "," << p.second << ")";
}
template <class T>
ostream& operator<<(ostream& o, const vector<T>& vc)
{
    o << "sz = " << vc.size() << endl
      << "[";
    for (const T& v : vc)
        o << v << ",";
    o << "]";
    return o;
}
using ll = long long;
constexpr ll MOD = 1000000007;

inline ll gcd(ll a, ll b)
{
    if (a == 0 or b == 0) {
        return max(a, b);
    }
    while (a != b) {
        if (a < b) {
            b = ((b - 1) % a) + 1;
        } else {
            a = ((a - 1) % b) + 1;
        }
    }
    return a;
}

int main()
{
    ll P, Q;
    cin >> P >> Q;
    const ll g = gcd(P, Q);
    const ll d = gcd(P + Q, P + 3 * Q);
    int N;
    cin >> N;
    ll num = 0;
    rep(i, N)
    {
        ll x, y;
        cin >> x >> y;
        if (g == 0) {
            if (x == 0 and y == 0) {
                num++;
            }
        } else {
            if (x % g == 0 and y % g == 0) {
                if ((x + y) % d == 0) {
                    num++;
                }
            }
        }
    }
    cout << num << endl;
    return 0;
}