Common App: What do I put under "Final" grade

Under the courses and grades section, it asks you to submit your grades from your first semester, second semester, and then your “Final” grade in that course. Is this asking you to average out your first and second-semester grades? If so, what happens if you have a B+ and an A-? If your school does not report a “Final” grade, should you leave this section blank?
Thank you.