maximum is 6+6+6 = 18. 
Kevin has $3$ regular dice. Each dice has numbers from $1$ to $6$. Which of the following could not be the sum of the numbers on top of the $3$ dice? 
  - $$5$$ 
  - $$13$$ 
  - $$17$$ 
  - $$22$$ 
  - All the above numbers are possible sum 