Google-sheets – Count Occurrences of Unknown Values

I'm really new to Google Sheets and formulas in general.
I know you can count occurrences of values when you know what you're counting e.g. the times red is written in the column and you can search for the word specifically, but I just want to make a count of how many times things appear.
For example;

Sarah  
Sally
Mike
Dolly
Sarah
Frances
Frances
Jemima
Sarah

My list would continue and I don't know what name is going to come next or I won't be keeping track of the names being put on so I can't tell it to search for a specific name.
Is there a way to tell Google Sheets to keep a tally of the occurrences and keep track and update when a new name is added to the list?