paramāyur vayaḥ-śatam.

evam-thus; vidhaih-by the process of; ahah-days; ratraih-by nights; kala-gatya-advancement of time; upalaksitaih-by such symptoms; apaksitam-declined; iva-just like; asya-his; api-although; paramayuh-duration of life; vayah-years; satam-one hundred.