Definition: In this task, you need to remove 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: 'a fork and knife rest on slices of pizza with cans and a salad bowl behind them'. Remove all words of length '6' in the given sentence.

a fork and knife rest on of pizza with cans and a salad bowl them