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

    if x%p == 0 and f == 0:
        ans = m
    print(ans)