Converting Non-Number Cell Value to Number For Sum

I have an Excel sheet with a list of names in different categories. I'd like to select these sections of names (eg. A3:A17, A25:A30, etc) and at the bottom, have a count of how many names there. Is there a way to write, "If there is any value in a cell, count it as one, then add them up"? I have been counting the names and just writing the number at the end, but the value keeps changing and I figured Excel is probably more efficient at counting than me.. thanks!!!