N,M,P,Q = map(int, input().split())

# (x * y) % P = f
# n^(P-1) mod P = 1
# given x and f, y = ?

# x * x^(P-2) mod P = 1
# x * f * x^(P-2) mod P = f

for _ in range(Q):
    x,f = map(int, input().split())
    y = f * x**(P-2) % P
    #print(f"{y=}")
    assert x * y % P == f
    if y == 0: y = P

    print((M-y)//P +1)