Decrypting the Reply

Your friend has replied, with the same shift. The reply is in a new array, reply. To decrypt it, every letter has to move back by shift places: from d back to a, and from a back to x. Add the decrypted reply to what the program prints:

Message: Meet me at the zoo by six
Secret: Phhw ph dw wkh crr eb vla
Reply: Ok, I will bring the map

A tip: the alphabet goes round in a circle of 26 letters, so you can also get back by moving forward. Then the function from the previous exercise decrypts too.