changing value and rerunning the code

[Arifattal]

i need this for something else i am working on, so i added it into a more simple code,
what i am trying to do is tell the code that if self.w(the third number) is greater than 20, self.z(the second number) will equal 0(in case the user wants that).
now i want the code to run again with the value the user previously put in, and with self.z = o.

class First():
    def number_input(self):
        self.x = int(input("whats your first number?\n"))
        print('your first number is', self.x)

class Second():
    def result(self):
           self.z = self.x + 2
           print('your second number is', self.z)

class Third():
    def last_result(self):
        self.w = self.z + self.x
        print('your third number is',self.w)

class if_over(First, Second, Third):
    def over(self):
        if self.w > 20:
            yes_no = (input("do you want your second number to equal 0?\n"))
            if yes_no == 'yes':
                self.z = 0





obj = if_over()
obj.number_input()
obj.result()
obj.last_result()
obj.over()