n, m, p, q = map(int, input().split())
for _ in range(q):
  x, f = map(int, input().split())
  if x % p == 0:
    print(0 if f else m)
    continue
  y = f * pow(x, p-2, p) % p
  print(m // p if y == 0 or y > m % p else m // p + 1)