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



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):
        cnt += 1
print(cnt)