#! 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

P, Q = gis
N = gi

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

if P == 1 || Q == 1 || d == 1
    p N
    exit
end
    
c = 0

N.times do
    x, y = gis.map(&:abs)
    if P == 0 && Q == 0
        c += 1 if x == 0 && y == 0
        next
    end
    xd, xm = x.divmod d
    yd, ym = y.divmod d
    c += 1 if xm == 0 && ym == 0 && (xd - yd).abs % 2 == 0
end

p c