def gcd(a, b):
    # 最大公約数
    while b > 0:
        a, b = b, a % b
    return a


def is_reachable(p, q, x, y):
    if p == 0:
        if q == 0:
            return x == 0 and y == 0
        else:
            return x % q == 0 and y % q == 0
    gap = gcd(p, q)
    if p % 2 == q % 2:
        if gap == 1:
            return x % 2 == 0 and y % 2 == 0
        elif gap == p:
            gap = 2*p
            return (x%gap == 0 and y%gap==0) or  ((x+p)%gap ==0 and (y+p)%gap==0)
        else:
            return (x % p == 0 and (y + gap) % p==0) or ((x + gap) % p == 0 and y % p==0)
    else:
        if gap == 1:
            return True
        elif gap == p:
            return x % p == 0 and y % p == 0
        else:
            return (x % p == 0 and (y + gap) % p==0) or ((x + gap) % p == 0 and y % p==0)


P, Q = map(int, input().split())
if P > Q:
    P, Q = Q, P
N = int(input())
cnt = 0
for i in range(N):
    x, y = map(int, input().split())
    if is_reachable(P, Q, x, y):
        # print(x, y, 'is good child')
        cnt += 1
print(cnt)