(1 2 3 4 5 6 7 9)
(2 3)
(1 5 7)
(1 2 3 4 5 6)
(1 2 3 4 5 6 7 10)
(2 5)
(1 4 6)
(1 2 3 5 7)
t
3
(2 3 5)
((2 . 2))
t
nil