a-a a-b a-t aaa aab aao aas aat aau ab- aba abb abo abs abt abu aoa aob aoo aos aot aou as- asa asb aso ass ast asu at- ata atb ato ats att atu au- aua aub auo aus aut b-u baa bab bao bas bat bau bba bbb bbo bbs bbt bbu boa bob boo bos bot bou bsa bsb bso bss bst bsu bta btb bto bts btt btu bua bub buo bus but buu oaa oab oao oas oat oau ob- oba obb obo obs obt obu oo- ooa oob ooo oos oot os- osa osb oso oss ost osu ot- ota otb oto ots ott otu ou- oua ouo ous out saa sab sao sas sat sau sba sbb sbo sbs sbt sbu soa sob soo sos sot sou ss- ssa ssb sso sss sst ssu sta stb sto sts stt stu sua sub suo sus sut suu taa tab tao tas tat tau tba tbb tbo tbs tbt tbu to- toa tob too tos tot tou tsa tsb tso tss tst tsu tta ttb tto tts ttt ttu tua tub tuo tus tut tuu ua- uaa uab uao uas uat uau uba ubb ubo ubs ubt ubu uoa uob uoo uos uot usa usb uso uss ust usu uta utb uto uts utt utu uua uus uut uuu