yamunāyāṁ śataṁ samāḥ

sri-sukah uvaca-Sri Sukadeva Gosvami said; evam-thus; gate-had accepted the order of vanaprastha; atha-thereafter; sudyumne-when Sudyumna; manuh vaivasvatah-Vaivasvata Manu, known as Sraddhadeva; sute-his son; putra-kamah-desiring to get sons; tapah tepe-executed severe austerities; yamunayam-on the bank of the Yamuna; satam samah-for one hundred years.