$(7)$ ElGamal public key cryptosystem $($decryption$)$:

Start with the prime $p=13$ and the primitive root $g=2.$

Alice's secret key is $a=4.$

Alice sends Bob the public key $A=3.$

Bob encrypts the message $m$ and sends the pair of numbers $(8,11)$ to Al$-$

ice. Using ElGamal public key decryption, Alice computes the plaintext

message $m$ from the ciphertext $(8,11).$ What is the number $m$ that Alice

obtains?