Using band math

I use sentinel image 1 and want to assign the value by bandmath as follows:
if VHmax> a then 1 elif VHmin> b then 2 else VHmin <c then NaN.
How can I express it with bandmath?

does this work?
IF VHmax> a THEN 1 ELSE (IF VHmin> b THEN 2 ELSE (IF VHmin < c THEN NaN ELSE 0))

I had to define the last ELSE 0 because each IF needs an ELSE.

Thank you so much for our solution!!
Maybe, but whatif I wish to find the VHmax as a function as well? Should it:
IF max(VH)> a THEN 1 ELSE (IF min(VH) > b THEN 2 ELSE (IF min(VH) < c THEN NaN ELSE 0))