You might have been enrolled into a malling list at some point in your life. While some malling lists are very helpful with the emails they send, some are simply used to send ads or spam. We'll code a very simple malling list which allows the adding or removal of emails to it$.$

Note: You do not need to verify that the information being entered is a valid email address.

Your program will feature a list which remembers every entrythat is added to it$.$ It will also contain a loop with the following options:

$$ Add entry: prompts the user for an email address, and then adds it to the list.

$$ Remove entry: prompts the user for an email address. If the email exists in the list, remove it$.$ Otherwise, print out an error message.

List entries: List all emails in the mailing list.

Quit: Quits the program.