$($This is Problem $6\mathrm{.}9,2$nd edition, or $7\mathrm{.}94$th edition$)$ Decrypt the ElGamal ciphertext

presented in Table $6\mathrm{.}3$ of page $270(2$nd edition$)$ or Table $7\mathrm{.}4$ of page $305(4$th edition$).$ The

parameters of the system are $p=31847,=5,a=7899$ and $=18074.$ Each element of $Z_n$

represents three alphabetic characters encoded as in the following examples:

DOG$3{26}^2+1426+6=2398$CAT$2{26}^2+026+19=1371ZZZ25{26}^2$

$+2526+25=17575$

You will need to invert this process as the final step in your program.