Definition: 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.
Input: Sentence: 'man sitting on last step in front of door while holding his phone'. Reverse all words of length '5' in the given sentence.

man sitting on last step in tnorf of door elihw holding his enohp