adding user to a class

[Nickd12]

once a class is made how to I add contacts to it in the future with input as apposed to manually inputting the code for example lets say I wanted to add john doe with inputs from a user and store it instead of doing it manually also I want to be able to store a couple so setting john to a variable and grabbing data from that list wouldn't work, also is there a way to keep that stored data if I need to rerun the program I have seen code for address books however the data thats stored in a list is lost once the program is re ran 

 
class Contacts:
    contactCont= 0
    def __init__(self, first_name,last_name, email):
        self.first_name = first_name
        self.last_name = last_name
        self.email = email

        Contacts.contactCont +=1
    def display_contact(self):
        print("First Name : ", self.first_name,", Last Name: ",self.last_name, ", Email: ", self.email)

    def name(self):
        n = self.first_name, self.last_name
        return n

    def email(self):
        e = self.email
        return e


john = Contacts("john", "Doe", "[email protected]")