Shiva Purana

siva.sh/siva-purana/rudra-samhita/145/30

मुहुः शिवेति भाषंतो देवा धैर्यसमन्विताः ।। कोटिसंख्यं तदा कृत्वा स्थितास्ते मुनिसत्तम ।। 2.5.7.३० ।।

sanskrit

O excellent sage, they stood there steady and repeated the mantra a crore times uttering the name “Śiva” several times.

english translation

muhuH ziveti bhASaMto devA dhairyasamanvitAH || koTisaMkhyaM tadA kRtvA sthitAste munisattama || 2.5.7.30 ||

hk transliteration by Sanscript