Alice wants to send a message to Bob in secure way.

Alice encrypted a plaintext P_{A}= ¡°IMISSYOU¡± = 0x494D495353594F55 by using DES and obtained ciphertext C_{A}= 0xFA26ED1833264435.

Alice sent the ciphertext C_{A}and the secret key to Bob. The secret key was encrypted by converting each of its letters to a pair of digits giving its position in the typewriter keyboard. More precisely, the following table is used.

1 2 3 4 5 6 7 8 9 0 1 Q W E R T Y U I O P 2 A S D F G H J K L 3 Z X C V B N M

In this manner, 'A' is converted to 21, 'B' to 35, etc. In transmission, all of the first digits were lost and the received secret key resulted in the pairs:

?8 ?9 ?9 ?4 ?3 ?5 ?9 ?5

After a few minutes, Bob recovered the secret key and smiled. Bob decided to reply in the same way.

Bob encrypts a plaintext P_{B}= 0xB6B2B6ACACA6B0AA by using DES and obtained ciphertext C_{B}= 0x05D912E7CCD9BBCA.

What is the secret key which Bob used? (0x????????????????) (Bob¡¯s secret key is different from Alice¡¯s secret key)

Answer: strupr(????????????????)