If a debt or any obligation that falls to one of the parties must be fulfilled after a certain period of time, starting with the establishment of the contract, the time for its performance is determined in the following form: 1. The period designated as a day expires on the last day of this period, regardless of the day the contract is established. If the period is set at EIGHT or FIFTEEN days, it means not ONE or TWO WEEKS, but exactly EIGHT or FIFTEEN DAYS. 2. The period specified as a week expires on the day of the last week that corresponds to the day the contract was established by name. 3. If the date of establishment of the contract is the sixth day of the month, the deadline of the last month will expire on the day that meets it. If there are no days in the last month that meet this deadline, the deadline is considered to have expired on the last day of this month. 4. The period from half a month to FIFTEEN DAYS is understandable. The day on which the period designated as one or more months and half a month has expired is determined by adding fifteen days to the last month. These rules also apply in cases where the period begins to operate at a time other than the establishment of the contract. The debtor is obliged to fulfill a debt that must be fulfilled within a certain period of time, before the expiration of this period