Valmiki Ramayana 7.66.13

तथा तस्य प्रहृष्टस्य शत्रुघ्नस्य महात्मनः ।व्यतीता वार्षिकी रात्रिः श्रावणी लघुविक्रमः॥

tathā tasya prahṛṣṭasya śatrughnasya mahātmanaḥ |vyatītā vārṣikī rātriḥ śrāvaṇī laghuvikramaḥ ||

Our plain-language meaning of this verse is waiting for scholar review.