Shiva Purana
पुनश्च नवकोट्या तु पृथिवीजयमाप्नुयात् । पुनश्च नवकोट्या तु ह्यपांजयमवाप्नुयात् १९ ।
A further repetition for nine crores of times enables him to win over the Earth element. A further repetition for nine crores of times enables him to win over the water element.
english translation
punazca navakoTyA tu pRthivIjayamApnuyAt । punazca navakoTyA tu hyapAMjayamavApnuyAt 19 ।
hk transliteration by Sanscript