Shiva Purana
शतमब्दं तपस्तप्त्वा कुशाग्रापः पिबेद्द्विजः ॥ तदाप्नोति फलं देवि विप्राणां धारणैकया ॥ ११ ॥
O goddess, by a single retention of vital airs, a brahmin attains the benefit accruing to him by the penance.performed for a hundred years while sustaining himself on the water from the tips of Kuśa grass.
english translation
zatamabdaM tapastaptvA kuzAgrApaH pibeddvijaH ॥ tadApnoti phalaM devi viprANAM dhAraNaikayA ॥ 11 ॥
hk transliteration by Sanscript