SICP 1.10b

SICP 1.10 b

(A x y)

(A 2 4)
  (A (- 2 1)
    (A 2 (- 4 1))

(A 1 
  (A 2 3)
  
(A 1
  (A (- 2 1)
    (A 2 (- 3 1)))
    
(A 1
  (A 1 (A 2 2))
  
(A 1
  (A 1 
    (A (- 2 1)
      (A 2 (- 2 1))
      
(A 1
  (A 1
    (A 1 
      (A 2 1))))
      
(A 1
  (A 1
    (A 1 2)
    
(A 1
  (A 1
    (A (- 1 1)
      (A 1 (- 2 1)
      
(A 1 
  (A 1
    (A 0 (A 1 1)
    
 (A 1
    (A 1
      (* 2 (A 1 1)
  
  (A 1
    (A 1 4))
    
 (A 1
  (A (- 1 1)
    (A 1 (- 4 1)
    
(A 1
  (A 0 (A 1 3)
  
 (A 1
  (* 2 (A 1 3)
  
  (A 1 
    (* 2
      (A (- 1 1)
        (A 1 (- 3 1)))
        
(A 1
  (* 2
    (A 0 (A 1 2)))
    
(A 1
  (* 2
    (* 2 (A 1 2)))
    
(A 1
  (* 2
    (* 2 
      (A (- 1 1)
        (A 1 (- 2 1)))
        
 (A 1
  (* 2
    (* 2 
      (A 0 (A 1 1)))
      
(A 1
  (* 2
    (* 2
      (* 2 (A 1 1)))
      
 (A 1
  (* 2
    (* 2
      (* 2 (2))))
      
  (A 1 16)
  
  I know that from the last question, (A 1 y) = 2 ^ y
  
  What are they testing here? Am I supposed to plow ahead and do (A 1 16) to the end?
  
  2^16 = 65536
  
  Which is the right answer.
  
  But did I take a shortbut or is this what they were actually testing