a-a a-b a-c aaa aab aac aad aak aar aay ab- aba abb abc abd abk abr aby ac- aca acb acc acd ack acr acy ad- ada adb adc add adk adr ady aka akb akc akd akk akr ar- ara arb arc ard ark arr ary ay- aya ayc ayd ayk ayr baa bab bac bad bak bar bay bba bbb bbc bbd bbk bbr bby bca bcb bcc bcd bck bcr bcy bda bdb bdc bdd bdk bdr bdy bka bkb bkc bkk bkr bra brb brd brk brr bry by- bya byc byd byk byr c-- caa cab cac cad cak car cay cba cbb cbc cbd cbk cbr cby cca ccb ccc ccd cck ccr cda cdb cdc cdd cdk cdr cdy cka ckb ckc ckd cky cra crb crc crd crk crr cry cya cyb cyc cyd cyk cyr daa dab dac dad dak dar day dba dbb dbc dbd dbk dbr dby dca dcb dcc dcd dck dcr dda ddb ddc ddd ddk ddr ddy dka dkb dkc dkk dkr dra drb drc drd drk drr dry dy- dya dyb dyc dyd dyk dyr dyy ka- kaa kab kac kad kak kar kay kba kbb kbc kbd kbk kbr kca kcb kcc kcd kck kcr kda kdb kdc kdk kdr kdy kkb kkc kkk kkr kky kra krc krd krk krr kry kya kyc kyd kyr ra- raa rab rac rad rak rar ray rba rbb rbc rbd rbk rbr rca rcb rcc rcd rcr rda rdb rdc rdd rdr rdy rkb rkc rkk rky rra rrb rrc rrd rrk rrr ry- rya ryc ryd ryk ryr ryy yaa yab yac yad yak yar yay ybc ybr yby yca ycc ycd ycy yda ydy yka ykk yra yrc yyb yyc yyy