a-a a-b a-t aaa aab aao aar aat aau aax ab- aba abb abo abr abt abu abx aoa aob aoo aor aot aou aox ar- ara arb aro arr art aru arx at- ata atb ato atr att atu atx au- aua aub auo aur aut aux ax- axa axo axr axt axx b-u baa bab bao bar bat bau bax bba bbb bbo bbr bbt bbu bbx boa bob boo bor bot bou box bra brb bro brr brt bru brx bta btb bto btr btt btu btx bua bub buo bur but buu bux bxb bxo bxx oaa oab oao oar oat oau oax ob- oba obb obo obr obt obu obx oo- ooa oob ooo oor oot oox or- ora orb oro orr ort oru orx ot- ota otb oto otr ott otu ou- oua ouo our out ox- oxa oxb oxo oxt oxx ra- raa rab rao rar rat rau rax rba rbb rbo rbr rbt rbu rbx roa rob roo ror rot rou rox rra rrb rrr rrt rru rta rtb rto rtr rtt rtu rtx rua rub ruo rur rut ruu rux rxr t-x taa tab tao tar tat tau tax tba tbb tbo tbr tbt tbu to- toa tob too tor tot tou tox tra trb tro trr trt tru trx tta ttb tto ttr ttt ttu ttx tua tub tuo tur tut tuu tux txt txu ua- uaa uab uao uar uat uau uba ubb ubo ubr ubt ubu ubx uoa uob uoo uor uot uox ur- ura urb uro urr urt uru urx uta utb uto utr utt utu utx uua uur uut uuu uxb uxo uxr uxt uxu xaa xar xat xau xbr xbx xoa xoo xor xot xox xrt xrx xtr xtx xxo xxx