n,m,p,q = map(int, input().split())

for _ in range(q):
  x,f = map(int, input().split())
  
  a = f*pow(x, -1, p)
  a%=p
  
  if(m<a):
    print(0)
    continue
  
  ans = m//p
  if(m%p >= (a+p-1)%p):
    ans+=1
  
  print(ans)