Need a formula that returns “N” when a sheet is deleted

Basically I have to have a formula that checks for any value in a set range on two separate sheets. It needs to return “Y” if there is any value and “N” if there is no value. The formula I was using was:

=IF(COUNTA(‘Sheet 4’!B35:B43,’Sheet 5’!B35:B43),”Y”,”N”)

This is for a template and the issue is that we delete unused sheets to make the document more clear to follow and for some reason, it returns as “Y” when the either or both sheets are deleted. If the sheet is deleted, I need it to return as “N”