Valmiki Ramayana Bala Kanda Sarga 46 Shloka 8
Original Shlokaगते तस्मिन्नरश्श्रेष्ठ दिति: परमहर्षिता। कुशप्लवनमासाद्य तपस्तेपे सुदारुणम्।।1.46.8।।
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नरश्श्रेष्ठ O Foremost of men, तस्मिन् when that Kasyapa, गते (सति) had gone, दिति: Diti, परमहर्षिता was exceedingly delighted, कुशप्लवनम् sacred spot named Kushaplavana, आसाद्य having reached, सुदारुणम् intense, तप: mortifications, तेपे practised.
"O foremost among men after Kasyapa had left, Diti exceedingly delighted (at the prospect of having sons) reached Kushaplavana, and practised intense mortifications.