Valmiki Ramayana Ayodhya Kanda Sarga 64 Shloka 2

अहम् I, अज्ञानात् in ignorance, तत् that, महत् great, पापम् sin, कृत्वा having done, सङ्कुलेन्द्रियः with agitated senses, एकस्तु myself alone, कथं नु how, सुकृतम् well done, भवेत् shall be, बुध्या in my mind, अचिन्तयम् reflected.

Having committed the sin unwittingly, I was greatly agitated. I reflected in my mind as to how to atone for this great sin.