Please use C#, my problem is the dark font part, how to express this in C#

Display the following statistics about the tree Number of items (note that this will be less than or equal to the number of items entered by the user, since duplicates wont be added to the tree). Write a function that determines this from your BST, NOT the array returned from the split. In other words, you must have a Count function in your BST implementation (you are not allowed to use any existing implementation for that). Number of levels in the tree. A tree with no nodes at all has 0 levels. A tree with a single node has 1 level. A tree with 2 nodes has 2 levels. A tree with three nodes could have 2 or 3 levels. You should know why this is from your advanced data structures prerequisite course.

Theoretical minimum number of levels that the tree could have given the number of nodes it contains (figure out the formula to calculate this)