a-a a-b a-c aaa aab aac aak aao aap aas aay ab- aba abb abc abk abo abp abs aby ac- aca acb acc ack aco acp acs acy aka akb akc akk ako akp aks aoa aob aoc aok aoo aop aos ap- apa apb apc apk apo app aps apy as- asa asb asc ask aso asp ass asy ay- aya ayc ayk ayo ayp ays b-p baa bab bac bak bao bap bas bay bba bbb bbc bbk bbo bbp bbs bby bca bcb bcc bck bco bcp bcs bcy bka bkb bkc bkk bko bkp bks boa bob boc bok boo bop bos boy bpa bpb bpc bpo bpp bps bpy bsa bsb bsc bsk bso bsp bss bsy by- bya byc byk byo byp bys c-- caa cab cac cak cao cap cas cay cba cbb cbc cbk cbo cbp cbs cby cca ccb ccc cck cco ccp ccs cka ckb ckc cko cks cky co- coa cob coc cok coo cop cos coy cpa cpb cpc cpk cpo cpp cps csa csb csc csk cso csp css csy cya cyb cyc cyk cyo cyp cys ka- kaa kab kac kak kao kap kas kay kba kbb kbc kbk kbo kbp kbs kca kcb kcc kck kcp kcs kkb kkc kkk kkp kks kky koa kob koc kok koo kop kos koy kpa kpc kpk kpo kpp kps ksa ksb ksc ksk kso ksp kss kya kyc kyo kyp kys oaa oab oac oak oao oap oas ob- oba obb obc obk obo obp obs oby oc- oca ocb occ ock oco ocp ocs oka okb okc okk oko okp oks oo- ooa oob ooc ook ooo oop oos op- opa opb opc opk opo opp ops opy os- osa osb osc osk oso osp oss oya oyo oys p-p paa pab pac pak pao pap pas pay pba pbb pbc pbk pbo pbp pbs pby pca pcb pcc pck pco pcp pcs pka pkb pkc pko pkp pks pky poa pob poc pok poo pop pos poy ppa ppb ppc ppk ppo ppp pps ps- psa psb psc psk pso psp pss psy py- pya pyb pyc pyk pyo pys saa sab sac sak sao sap sas say sba sbb sbc sbk sbo sbp sbs sby sca scb scc sck sco scp scs sk- ska skb skc skk sko skp sks sky soa sob soc sok soo sop sos soy spa spb spc spk spo spp sps spy ss- ssa ssb ssc ssk sso ssp sss sy- sya syb syc syk syp sys yaa yab yac yak yao yap yas yay ybc ybp ybs yby yca ycc yco ycp ycs ycy yka ykk yob yoc yok yoo yop yos yoy ypa ypo yps ysa ysb ysc ysk yso ysp yss ysy yyb yyc yys yyy