#include <bits/stdc++.h>
using namespace std;
using i64 = int64_t;
using vi = vector<i64>;
using vvi = vector<vi>;

int main() {
    i64 p, q;
    cin >> p >> q;
    int ZERO = p == 0 && q == 0;
    i64 g = -1;
    if (!ZERO) g = __gcd(p, q);
    int cnt = 0;
    int n;
    cin >> n;
    if (ZERO) {
        for (int i = 0; i < n; i++) {
            int x, y;
            cin >> x >> y;
            cnt += x == 0 && y == 0;
        }
    } else {
        for (int i = 0; i < n; i++) {
            int x, y;
            cin >> x >> y;
            if (x % g == 0 && y % g == 0 && ((p + q) / g % 2 == 1 || ((x + y + p + q) / g) % 2 == 0)) {
                cnt++;
            }
        }
    }
    cout << cnt << endl;
}