p,q = map(int,input().split())
N = int(input())

def gcd(a,b):
    if b == 0:return a
    while True:
        r =a % b
        a = b
        b = r
        if r == 0:return a
ans = 0
d = gcd(p,q)
flag = False
if d != 0:
    p //= d
    q //= d
    if (p+q) % 2 == 0:
        flag = True
for _ in range(N):
    x,y = map(int,input().split())
    if d == 0:
        if x == 0 and y == 0:ans += 1
        continue
    if x % d == 0 and y % d == 0:
        x //= d
        y //= d
        if flag:
            if (x+y)% 2 == 0:ans+= 1
        else:ans += 1
print(ans)