1. Review 

    ;; List -> Integer
    (define num-atoms
    	    (lamblda (L)
	    	     (cond ((empty? L) 0)
		     	   ((atom? (car L)) (+ 1 (num-atoms (cdr L))))
			   (else (num-atoms (cdr L))))))


    a. What is the length of '(1 (2 3 4) 5)?

    b. Complete a trace diagram of (num-atoms '(1 (2 3 4) 5)).



2. Write the function (num-odds L) that computes the number of odd
   integers in a list.

   Test Cases:
   (num-odds '() ) -> 0
   (num-odds (list 1 2 3 4 5 6)) -> 3
   (num-odds '(10 12 22)) -> 0
  
   ;; List -> Integer
   ;; Assume L is either empty or each item is an integer.
   (define num-odds
   	   (lambda (L)