mam, i hope his ( Rustam Ali ) doubt is, how you say it is ( 245 - 1).
Bye the way did you assume the root height = 1 ?
why height will need here?
We only need no of comparison
then how you got 245 -1
that is in-directly referring height, when height of root=1
if height of root=0, then it would be 2(h-1) - 1
it is bonded ===> O(1)