I am programming in Scheme, I am trying to make a function where you take a list of numbers, reverse the list, throw out the negative numbers and summation the non$-$negatives. Here is my code:

$($define $($sum n$)$

$($if $($eq$?$n $0)$

$0$

$(+$n $($sum $(-$n $1)))))$

$($define $($ReverseEm elems$)$

$($if $($null$?$elems$)$

$\text{'}()$

$($append $($ReverseEm $($cdr elems$))$

$($list $($car elems$)))))$

$($define $($nonNegative num$)$

$($if $(>=$num $0)$

num

$0))$

$($define $($JustDoIt lst$)$

$($if $($nonNegative $($ReverseEm $($sum lst$))))$

If I run $($JustDoIt $\text{'}(3-14602-5))$it say Ill$-$formed special form: if

The correct output should be $(30216)$

Because summation of $3$is $1+2+3=6,-14$gets thrown out, $1+2+3+4+5+6=21,0=0,1+2=3,-5$gets thrown out, the list gets reversed: $(30216),$I feel I am close, but I can't get the form right in scheme because I am unfimiliar with it$,$can you help me$?$