def extgcd(a, b):
    if b:
        d, y, x = extgcd(b, a%b)
        y -= (a/b)*x
        return d, x, y
    else:
        return a, 1, 0
inputs = lambda:map(int, raw_input().split())
p, q = inputs()
if p<q: p,q = q,p
g, a, b = extgcd(p, q)
n = input()
ans = 0
for i in xrange(n):
    xi, yi = inputs()
    if p==0:
        ans += (xi==yi==0)
    elif q==0:
        ans += (xi%p==0 and yi%p==0)
    else:
        if xi%g==0 and yi%g==0:
            xr = xi/g; yr = yi/g
            x  = xr*a; y = xr*b
            dx = q/g; dy = -p/g
            z = yr*b; w = yr*a
            dz = p/g; dw = -q/g
            #print x, dx, y, dy
            #print z, dz, w, dw
            if(((x+z)%2==0 and (y+w)%2==0) or
               ((x+z+dx)%2==0 and (y+w+dy)%2==0) or
               ((x+z+dz)%2==0 and (y+w+dw)%2==0) or
               ((x+z+dx+dz)%2==0 and (y+w+dy+dw)%2==0)):
                ans += 1
print ans