If 语句未按预期工作 (Python)

Question

This code I wrote for my study on if statements in Python doesn't seem to work properly since it asks the same question twice after the first one being asked.

Identity = input("Who are you? ")

if Identity == "Jane":
    print("You must be John's sister.")
elif Identity != "John":
    print("My database doesn't recognise you. Who are you I wonder...")
elif Identity == "John":
    if input("What is your last name? ") != "Travolta":
        print("False! John's name is Travolta and not " + input("What is your last name? ") + ".")
    elif input("How old are you? ") == "Travolta":
        if input("How old are you? ") != "20 yo":
            print("False! John is 20 yo and not " + input("How old are you? ") + ".")
        elif input("How old are you? ") == "20 yo":
            print("You must in fact be John!")

Answer 1

if input("What is your last name? ") != "Travolta":
    print("False! John's name is Travolta and not " + input("What is your last name? ") + ".")

Here you aren't storing the value of the input and printing it. You are asking the person to input again "what is your last name?".

Do something like

last_name = input("What is your last name? ")

and use it instead of the input() in the if statement.

Here I am putting the snippet in the way I would've done it.

identity = input("Who are you? ")

if identity == "Jane":
    print("You must be John's sister.")
elif identity != "John":
    print("My database doesn't recognise you. Who are you I wonder...")
elif identity == "John":
    last_name = input("What is your last name? ")
    if last_name != "Travolta":
        print("False! John's last name is Travolta and not " + last_name + ".")
    else:
        age = input("How old are you? ")
        if age != "20 yo":
            print("False! John is 20 yo and not " + age + ".")
        else:
            print("You must in fact be John!")

It is working properly for every possibility. Examples: