I'm trying to run, what to me seems, a very simple report, but cannot figure out how to do it.

For example I have an assembly A it's composed of a sub assembly and an additional part

Say the sub assembly is B which is composed of C & D and the additional part is E.

A= B+E or A= (C+D)+E

I'd like a report that tells me how many of each A,B,C,D,E I have in a warehouse. 

Is this possible?

The desired result would look like this

A=3

B=2

C=4

D=5

E=3