Valmiki Ramayana Ayodhya Kanda Sarga 40 Shloka 12
Original Shlokaचतुर्दश हि वर्षाणि वस्तव्यानि वने त्वया। तान्युपक्रमितव्यानि यानि देव्यासि चोदितः।।2.40.12।।
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चतुर्दश fourteen, वर्षाणि years, त्वया by you, वने in the forest, वस्तव्यानिव you will dwell, यानि those, देव्या by queen Kaikeyi, चोदितः असि you have been directed, तानि those, उपक्रमितव्यानि should be commenced.
You have been directed by Kaikeyi to live in the forest for fourteen years. Accordingly you must now commence counting those years as directed.