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

    XF = [list(map(int, input().split())) for _ in range(Q)]

    for i in range(Q):
        x, f = XF[i]

        y_0 = (f * pow(x, P-2, P)) % P

        if y_0 == 0:
            print((M - y_0) // P)
        else:
            print((M - y_0) // P + 1)
    return 0


main()