Valmiki Ramayana Kishkindha Kanda Sarga 6 Shloka 14
Original Shlokaएवमुक्तस्तु सुग्रीवश्शैलस्य गहनां गुहाम्। प्रविवेश ततशशीघ्रं राघवप्रियकाम्यया4.6.14।।
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एवम् in that way, उक्तः having asked, सुग्रीवः Sugriva, ततः then, राघवप्रियकाम्यया to make Rama happy, शैलस्य mountain's, गहनाम् deep, गुहाम् cave, शीघ्रम् at once, प्रविवेश entered
On hearing this, Sugriva at once entered into the deep cave of the mountain (to get the ornaments and veil) in order to please Rama.