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: 'many people flying kites in front of the white house in washington dc'. Reverse all words of length '4' in the given sentence.

ynam people flying kites in front of the white house in washington dc