In this task, you need to reverse all words of a given length in the sentence. The number of letters in a word determine its length. For example, the length of the word "apple" is 5.
--------
Question: Sentence: 'an image of a group of people sitting in the snow'. Reverse all words of length '6' in the given sentence.

Answer: an image of a group of elpoep sitting in the snow


Question: Sentence: 'a man assisting a person on a horse on a race track'. Reverse all words of length '3' in the given sentence.

Answer: a nam assisting a person on a horse on a race track


Question: Sentence: 'a man is cutting an onion on the cutting board'. Reverse all words of length '7' in the given sentence.

Answer:
a man is gnittuc an onion on the gnittuc board