The period prescribed by this Act or an order issued under this Act shall be computed as follows:
1. The first day of the period shall not be included in the computation: Provided, That the foregoing shall not apply where the period begins from 0:00 am;
2. Where the period is set in months or years, the period shall be computed in accordance with calendar units;
3. Where the period is not computed from the beginning of a month or year, the period shall expire on the day preceding the day corresponding to the day from which the reckoning is made in the last month or year: Provided, That where no day corresponds thereto in the last month if the period is set in months or years, the period shall expire on the last day of such month;
4. Where the last day of a period is a public holiday (including a Saturday and the Workers' Day under the Designation Workers' Day Act) in the trademark-related procedures, the period shall expire on the day following such public holiday.