Macro question in excel. How can I make the macro scroll to the first empty cell?

Question

excel

Good afternoon!
Please tell me how to stop the macro on the first empty cell, it seems to be registered, and it stretches to the end of the bottom of the sheet. Moreover, the U column is stretched correctly. And columns from V to AE are stretched to the end. If necessary, I will throw off the entire piece of the macro.

a = number of rows

Thank you!

a = Sheets("EFIN Delivery").Range("Z1")
Range("U5:U" & a).FillDown
Range("A5:A" & a).FillDown
Range("AK5:AK" & a) .FillDown
Range("V5:AE5" & a).FillDown
Range("U5:AK5" & a).Select