Coding issue

[1557676]

Hi guys! I'm new to python and coding in general. I'm trying to make a program which will register new users and login registered users. My issue is when I register a user using the program and attempt to login using the same username and password, the print says 'access denied' instead of what it should say, 'access granted'. I don't know what's the issue here. It would be great if you guys could help. Thanks! Here is the code:

a = input('Logging in or new user')
registration = []
passwords = []
if a == 'logging in':
    b = input('username')
    c = input('password')
    if b in registration:
        if c in passwords:
            print('Access granted')
        else:
            print('Access Denied')
    else:
        print('Access Denied')


if a == 'new user':
    d = input('New username')
    e = input('New password')
    f = input('confirm password')
    if e == f:
        print('Welcome ' + d)
        registration.append(d)
        passwords.append(e)

(edit: everything is properly indented)

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Thank you Yoriz! I will follow these instructions next time.