I want to have the number of students in a class to automatically update
when I add or remove a row. In other words, I want the value for "count" to
always be correct. I see how I could do this by making an =row() column,
but that wouldn't be idiot proof. Any new row would have to have that value
added by the user. Is there any way to count rows that have no numeric
value in them?

Example

First Name Last Name
Alma Diderot
Mark Woolser
Amy Fleisher
Count 3