Auto Generate an ID# based on date

HI all,

I'm working on a spreadsheet where I want to auto generate an ID# based on the date. For instance... In Column A, I input the date the data was entered, In column B, I want an ID# that reflects the date and the sequence of entries for that day, ie. 161013-1 or 1610131 and if there were another entry for that day 161013-2. If there were any entries the following day it would start back at 1, 161014-1

Thanks for any help you're able to provide.

Jamie