I've been learning about the concept of Wheatstone bridge in current electricity chapter. I attempted to solve this problem by that concept:

I don't know if my method is right. I tried to take the resistances inside the dotted lines as one unit( represented by a box) :

Since all the resistances have the same value and by Balanced WB , the 'box' is neglected. However I feel like this is a wrong method. Is it so ? If not please state an alternate formulae ( the question is to calculate equivalent resistance between A and B where all resistance are same