You can get the password via one of the online Python interpreters.
This one is easy to use:
https://www.tutorialspoint.com/execu...hon_online.php
Just type in the instructions as given in the tutorial:
import hashlib
print("fiona%s"%hashlib.md5("<your kindle serial number with no spaces and all capital letters>\n".encode('utf-8')).hexdigest()[13:16]
Then click on the 'Execute' button and it should print your password.