Find Duplicates but Ignore Blanks

Hi y'all,

I am using an IF function nested on a COUNTIF function to find duplicates, but it is registering cells that are blank as duplicate. Is there any way to make the formula ignore blanks? I just want the formula to tell me if value is duplicated or unique while totally ignoring the blanks, something like "<>".

Here is my formula:

 =IF(COUNTIF($F$2:$F$17731,$F2)>1,"duplicate","unique")

Thanks!