6 21. The Court is competent to hear the instant case. Peru ratified the Convention on July 28, 1978, and accepted the jurisdiction of the Court on January 21, 1981. IV 22. Before examining the preliminary objection brought by the Government, it is appropriate to consider a previous matter raised by both parties, in writing and at the hearing, concerning the admissibility of the filing of the objection. 23. On March 22, 1995, the Commission requested the Court to rule that the Government's right to file preliminary objections had been extinguished, on the grounds that the period of thirty days for filing them had already expired. In its brief of March 24, 1995, received at this Court on April 3, the Government alleged that it had presented the preliminary objection on time. In support of this claim, it argued that there was a distinction between the deadline established in the Rules of Procedure of this Court for answering to the application [Article 29(1)], set at three months, and the deadline for filing preliminary objections [Article 31(1)], set at thirty days, proving that there was a difference, well supported by procedural doctrine, between dates established in days and those established in months or years; whereas the former include only working days, the latter are reckoned in calendar days. 24. The Government also contends that this difference is consistent with Peru's legislation and jurisprudence whereby procedural periods established in days are reckoned excluding non-working days; however, when the reference is to months or years those days are included; in other words, they are calendar days. The Government concluded that in the Rules of Procedure of this Court a clear distinction is drawn between the period for answering the application and the period for filing preliminary objections, with the deliberate intention of following the generally accepted procedure that when a period is indicated in months it includes all the days in the Gregorian calendar, holidays and working days alike, but that when it is established in days -as is the case with preliminary objections- only working days are taken into account. According to that hypothesis, the brief of preliminary objections had been presented on time. 25. On April 24, 1995, the Inter-American Commission, for its part, reiterated its request of March 22, 1995, and also asked that the brief presented by Peru on March 24 be declared inadmissible, on the grounds that it had not been presented within the deadline established by the Rules of Procedure of this Court. The Commission maintains that the Government received notification of the application on February 13, 1995, so that when the preliminary objection was presented on March 24, 1995, -without any request for a deferment or extension of the deadline- the period of thirty days established in Article 31(1) of the Rules of Procedure had long expired, and, consequently, Peru's right to file the objection had been extinguished. 26. The Commission invoked the thesis sustained by the Court in the Cayara case, to the effect that “there must be a fair balance between the protection of human rights, which is the ultimate purpose of the system, and the legal certainty and procedural equity that will ensure the certainty and reliability of the international protection mechanism” (Cayara Case,