MAX(12,6,7,9) -> 12
MAX(17.3,19,17.03) -> 19
MAX(-7,-3,-4.3) -> -3
MAX(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,MAX(20,21)) -> 21
Implementation maximum: You can specify up to 20 numbers, and can nest calls
to MAX if more arguments are needed.