Shiva Purana
शिवे संकल्पितं पूर्वं पुराणं ग्रन्थसंख्यया । शतकोटिप्रमाणं हि पुरा सृष्टौ सुविस्मृतम् ५७ ।
The Purāṇic lore at the time of the first creation as conceived by Śiva contained a thousand million (hundred crores) verses.
english translation
zive saMkalpitaM pUrvaM purANaM granthasaMkhyayA । zatakoTipramANaM hi purA sRSTau suvismRtam 57 ।
hk transliteration by Sanscript