;(mod (tree)
;    (defun pubkey-tree (tree)
;        (if (l tree) (pubkey_for_exp (concat (pubkey-tree (f tree)) (pubkey-tree (r tree)))) (pubkey_for_exp tree))
;    )
;    (pubkey-tree tree)
;)

(a (q 2 2 (c 2 (c 5 (q)))) (c (q 2 (i (l 5) (q 30 (concat (a 2 (c 2 (c 9 (q)))) (a 2 (c 2 (c 13 (q)))))) (q 30 5)) 1) 1))