b-u bbb bbm bbn bbr bbs bbu bmb bmm bmn bmr bms bmu bnb bnn bnr bns bnu brb brm brn brr brs bru bsb bsm bsn bsr bss bsu bub bum bun bur bus buu m-r mbb mbm mbr mbs mbu mmb mmm mmn mmr mms mmu mnb mnm mnn mnr mns mnu mrb mrm mrn mrr mrs mru msb msm msn msr mss msu mub mum mun mur mus muu nbb nbm nbn nbr nbs nbu nmb nmm nmn nmr nms nmu nnb nnm nnn nns nnu nrb nrm nrn nrr nrs nru nsb nsm nsn nsr nss nsu nub num nun nur nus nuu rbb rbm rbn rbr rbs rbu rmb rmm rmn rmr rms rnb rnm rnn rnr rns rnu rrb rrm rrn rrr rrs rru rsb rsm rsn rsr rss rsu rub rum run rur rus ruu sbb sbm sbn sbr sbs sbu smb smm smn smr sms smu snb snm snn snr sns snu sr- srb srm srn srr srs ss- ssb ssm ssn ssr sss ssu sub sum sun sur sus suu ubb ubn ubr ubs ubu um- umb umm umn umr ums umu un- unb unm unn unr uns unu ur- urb urm urn urr urs uru usb usm usn usr uss usu uum uun uur uus uuu