how to get the last sub folder value from the string in Webi report

I have an object coming from universe, this object will contain string e.g. \\Users\Public\Pictures\Sample\

or    \\Users\Doc\BI\BO\Webi\

I need the last sub folder from this path to be displayed i.e. Sample and Webi.

I would like to know how it can be done.

I tried using formulas like POS, SubStr and Length. however the issue is that the length of the the sting is not fixed and the number of "\" are also not fixed.

I would appreciate any help regarding this.

Regards,

Yogesh