a-a a-b a-c aaa aab aac aah aak aar ab- aba abb abc abh abk abr ac- aca acb acc ach ack acr aha ahb ahc ahh ahk ahr aka akb akc akh akk akr ar- ara arb arc arh ark arr baa bab bac bah bak bar bba bbb bbc bbh bbk bbr bca bcb bcc bch bck bcr bha bhb bhc bhh bhk bhr bka bkb bkc bkk bkr bra brb brh brk brr c-- caa cab cac cah cak car cba cbb cbc cbh cbk cbr cca ccb ccc cch cck ccr ch- cha chb chc chh chk chr cka ckb ckc ckh cra crb crc crh crk crr haa hab hac hah hak har hba hbb hbc hbh hbk hbr hca hcb hcc hch hck hcr hha hhb hhc hhh hhk hhr hka hkb hkh hkk hkr hr- hra hrb hrc hrh hrk hrr ka- kaa kab kac kah kak kar kba kbb kbc kbh kbk kbr kca kcb kcc kch kck kcr kha khh khk khr kkb kkc kkh kkk kkr kra krc krk krr ra- raa rab rac rah rak rar rba rbb rbc rbh rbk rbr rca rcb rcc rch rcr rh- rha rhb rhc rhh rhr rkb rkc rkk rra rrb rrc rrh rrk rrr