I don't want to get a record count of the total records, but rather than +1 of the certain field

Example:

Helpdesk Ticket # 1002 is submitted

Next Ticket will be Helpdesk ticket #1003

I need a way on load (or validate) to reference the helpdesk ticket number of th last submitted ticket, and then add +1 to the value

Any help would be great.

Thank you.