ISBLANK Nesting

Good Morning All, 

I am new to Smartsheets and would like some assistance on what I thought would be straight forward and I know I am missing something basic.

So the formula in English:

Is DATE 2 Blank 

YES - then NETDAYS between DATE 1 and TODAY in DAYS

NO -  the NETDAYS between DATE 1 and DATE 2 in DAYS

So I thought it would be written as:

IF(ISBLANK([DATE 2]1), (NETDAYS([DATE1]1, TODAY()), (NETDAYS([DATE 1]1),([DATE 2]1))) 

All I get is Unparseable, why is my logic failing, it seems like it has continuity, but obviously not.  Any help would be great appreciated.

Blue