I$\text{'}$m having an issue with correctly simplifying the arithmetic expression in the Lisp code below could you help solve the issue? The description of the program and the code are included $($PLZ add a screenshot of the code running properly$)$

THE DESCRIPTION :

Create a LISP program for the simplification and evaluation of arithmetic expressions

$($PEMDAS$).$

The program, when executed, should prompt the user to enter an arithmetic expressions

$("$Enter arithmetic expression: $")$The expression should be a linear combination of single letter variables. The program will then simplify the expression $($like below$)$:

Enter arithmetic expression: $2$x $+13+$ y $-$ x

Simplification: x $+$ y $+13$

and then it will ask whether to evaluate the expression. If the answer is $\text{'}$y$\text{'}$ then it will prompt for values for each of the variables and evaluate the expression, then ask for a new expression to evaluate. If the answer is $\text{'}$n$\text{'},$ then it will simply ask for a new expression to evaluate. The program will quit with command 'quit' entered at the expression prompt.

Example of I$/$O$($in the case of $$y$$:

Enter arithmetic expression: $2$x $+13+$ y $-$ x

Simplification: x $+$ y $+13$

Evaluate? y

Provide variable values

x : $1$

y : $3$

Expression value: $18$

$***$

Enter arithmetic expression:

THE CODE:

$($defun simplify$-$expression $($expr$)$

"Function to simplify arithmetic expression"

$($let$*(($terms $($split$-$sequence:split$-$sequence #$\backslash +$ expr$))$

$($simplified$-$terms $($mapcar #$\text{'}($lambda $($term$)$

$($string$-$trim $""$ term$))$

terms$))$

$($final$-$simplified $($format nil $"$~$\{$~a~$^+$ ~$\}"$ simplified$-$terms$)))$

final$-$simplified$))$

$($defun evaluate$-$expression $($expr values$)$

"Function to evaluate arithmetic expression"

$($let$*(($tokens $($split$-$sequence:split$-$sequence #$\backslash +$ expr$))$

$($evaluated$-$tokens $($mapcar #$\text{'}($lambda $($token$)$

$($eval $($read$-$from$-$string token$)))$

tokens$))$

$($result $($apply #$\text{'}+$ evaluated$-$tokens$)))$

result$))$

$($defun main $()$

"Main function to run the program"

$($format t "Enter arithmetic expression $($or 'quit' to exit$)$:~$\%")$

$($loop

$($format t $">")$

$($finish$-$output$)$

$($let $(($input $($read$-$line$)))$

$($if $($string$=$ input "quit"$)$

$($progn

$($format t "Good Bye!~$\%")$

$($return$)))$

$($let$*(($simplified $($simplify$-$expression input$)))$

$($format t "Simplification: ~a~$\%"$ simplified$)$

$($format t "Evaluate? $($y$/$n$)$: $")$

$($finish$-$output$)$

$($let $(($choice $($char$-$downcase $($read$-$char$))))$

$($cond

$(($char$=$ choice #$\backslash$y$)$

$($let$*(($vars $($remove$-$duplicates $($remove$-$if$-$not #'alpha$-$char$-$p $($coerce simplified 'list$)))))$

$($format t "Provide variable values~$\%")$

$($let $(($values $($make$-$hash$-$table :test 'equal$)))$

$($loop for var in vars do

$($progn $($format t $"$~a: $"$ var$)$

$($setf $($gethash var values$)($read$))))$

$($format t "Expression value: ~a~$\%***$~$\%"($evaluate$-$expression simplified values$))))$

$(($char$=$ choice #

$)$

nothing$))$

$($t $($format t $"***$~$\%"))))))))$

$($main$)$