#! ruby
# yukicoder My Practice
# author: Leonardone @ NEETSDKASU

def gs(); gets.chomp; end
def gi(); gets.to_i; end
def gss(); gets.chomp.split; end
def gis(); gss.map(&:to_i); end

# 解説読後
# http://yukicoder.me/problems/849/editorial

P, Q = gis
N = gi

d = P * Q == 0 ? P + Q : P.gcd(Q)

if P == 1 || Q == 1 || d == 1
    puts N
    exit
end

c = 0

N.times do
    x, y = gis.map(&:abs)

    c += 1 if x % d == 0 && y % d == 0
end

p c