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

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

# size = 100
# inf = 1000
# town = [[inf for j in range(size)] for i in range(size)]
# town[0][0] = 0
# for i in range(50):
#     for j in range(size):
#         for k in range(size):
#             for dy, dx in ((P, Q), (P, -Q), (-P, Q), (-P, -Q), (Q, P), (Q, -P), (-Q, P), (-Q, -P)):
#                 if town[j][k] < inf and 0 <= j + dy < size and 0 <= k + dx < size:
#                     town[j + dy][k +
#                                  dx] = min(town[j + dy][k + dx], town[j][k] + 1)


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
    #     if town[y][x] == inf:
    #         print(x, y, 'is NOT good child')
    # elif town[y][x] < inf:
    #     print(x, y, 'is good child')
print(cnt)
#
# for i in range(min(30, size)):
#     for j in range(min(30, size)):
#         print((' ' + str(town[i][j]))[-2:], end=' ')
#     print()