import std.conv, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.container, std.math, std.numeric, std.range, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken().to!int; }
long readLong() { return readToken().to!long; }
real readReal() { return readToken().to!real; }

void chmin(T)(ref T t, in T f) { if (t > f) t = f; }
void chmax(T)(ref T t, in T f) { if (t < f) t = f; }

int binarySearch(T)(in T[] as, in bool delegate(T) test) { int low = -1, upp = cast(int)(as.length); for (; low + 1 < upp; ) { int mid = (low + upp) >> 1; (test(as[mid]) ? low : upp) = mid; } return upp; }
int lowerBound(T)(in T[] as, in T val) { return as.binarySearch((T a) => (a < val)); }
int upperBound(T)(in T[] as, in T val) { return as.binarySearch((T a) => (a <= val)); }


bool check(long p, long q, long x, long y) {
  if (p == 0 && q == 0) {
    return (x == 0 && y == 0);
  } else {
    const g = gcd(p, q);
    if (!(x % g == 0 && y % g == 0)) {
      return false;
    }
    p /= g;
    q /= g;
    x /= g;
    y /= g;
    if ((p + q) % 2 == 0) {
      if ((x + y) % 2 != 0) {
        return false;
      }
    }
    return true;
  }
}

long P, Q;
int N;
long[] X, Y;

void main() {
  try {
    for (; ; ) {
      P = readLong();
      Q = readLong();
      N = readInt();
      X = new long[N];
      Y = new long[N];
      foreach (i; 0 .. N) {
        X[i] = readLong();
        Y[i] = readLong();
      }
      int ans;
      foreach (i; 0 .. N) {
        if (check(P, Q, X[i], Y[i])) {
          ++ans;
        }
      }
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}