#!/usr/bin/env python3
# %%
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines
from math import gcd

# %%
P, Q = map(int, readline().split())
N = int(readline())
m = map(int, read().split())
XY = list(zip(m, m))

# %%
d = gcd(P, Q)
if d == 0:
    answer = sum(x == y == 0 for x, y in XY)
    print(answer)
    exit()
P //= d
Q //= d
is_even = (P + Q) % 2 == 0


# %%
def check(X, Y, d, is_even):
    if X % d != 0:
        return False
    if Y % d != 0:
        return False
    X //= d
    Y //= d
    if is_even:
        return (X + Y) % 2 == 0
    else:
        return True


# %%
answer = sum(check(x, y, d, is_even) for x, y in XY)
print(answer)