How is the calculation of a lunar year lease determined when the starting time is known?

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If a person leases property at the beginning of a lunar month, twelve lunar months are counted, irrespective of whether the month is complete or deficient, because a lunar month is the period between two sightings of the new moon. If the contract begins in the middle of a month, the remainder of that month is counted, followed by eleven full lunar months, and then the first month is completed by counting thirty days, as completion by sighting was impossible, necessitating completion by counting, allowing the remainder to be fulfilled by the lunar count as it is the default standard.