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You are given a paragraph, with numbered sentences, and a question. Write the numbers of the sentences needed to answer the given question. Separate multiple sentence numbers with a comma (", "). E.g. "1, 2" would be the correct response if Sent 1 and Sent 2 are needed to answer the given question (do not include sentences that contain no information that is necessary to answer the question). Sort the sentence numbers in an increasing order (i.e., '1, 2', instead of '2, 1'). Your answer should not contain anything than the sentence numbers separated by a comma (e.g. '1, 2, 3, 4'). The given question requires more than one sentence to answer. So, your answer must contain at least one comma (", ").

Paragraph- Sent 1: While glaciers erode the landscape, they also deposit materials.
Sent 2: Glaciers deposit their sediment when they melt.
Sent 3: They drop and leave behind whatever was once frozen in their ice.
Sent 4: Its usually a mixture of particles and rocks.
Sent 5: It can be of all sizes, called glacial till.
Sent 6: Water from the melting ice may form lakes or other water features.
Sent 7: Figure Moraine is sediment deposited by a glacier.
Sent 8: A ground moraine is a thick layer of sediments left behind by a retreating glacier.
Sent 9: An end moraine is a low ridge of sediments deposited at the end of the glacier.
Sent 10: It marks the greatest distance the glacier advanced.
Sent 11: A drumlin is a long, low hill of sediments deposited by a glacier.
Sent 12: Drumlins often occur in groups.
Sent 13: These groups are called drumlin fields.
Sent 14: The narrow end of each drumlin points in the direction of an advancing glacier.
Sent 15: An esker is a winding ridge of sand deposited by a stream of meltwater.
Sent 16: Such streams flow underneath a retreating glacier.
Sent 17: A kettle lake occurs where a chunk of ice melt as they are left behind as a glacier retreats.
Sent 18: When the huge chuck of ice melts it leaves a depression. 
Question: What do glaciers do besides eroding?.
Output:
1, 2, 3.