:cs 4 5 n
:cs 7 10 n
:cs 10 6 n
:cs 13 7 n
:cs 16 8 n
:cs 20 12 a
:cs 23 16 a
:cs 26 12 a
:cs 29 13 a
:cs 32 14 a
:cs 36 10 n
:cs 39 13 a
:cs 42 13 b
:cs 45 14 a
:cs 48 14 b
:cs 51 16 a
:cs 54 16 b
:cs 57 20 a
:cs 60 20 b
:q