a-a a-b a-c aaa aab aac aap aar aay ab- aba abb abc abp abr aby ac- aca acb acc acp acr acy ap- apa apb apc app apr apy ar- ara arb arc arp arr ary ay- aya ayc ayp ayr b-p baa bab bac bap bar bay bba bbb bbc bbp bbr bby bca bcb bcc bcp bcr bcy bpa bpb bpc bpp bpr bpy bra brb brp brr bry by- bya byc byp byr c-- caa cab cac cap car cay cba cbb cbc cbp cbr cby cca ccb ccc ccp ccr cpa cpb cpc cpp cpr cra crb crc crp crr cry cya cyb cyc cyp cyr p-p paa pab pac pap par pay pba pbb pbc pbp pbr pby pca pcb pcc pcp pcr ppa ppb ppc ppp ppr pra prb prc prp prr pry py- pya pyb pyc pyr ra- raa rab rac rap rar ray rba rbb rbc rbp rbr rca rcb rcc rcp rcr rpa rpb rpc rpp rpr rra rrb rrc rrp rrr ry- rya ryc ryr ryy yaa yab yac yap yar yay ybc ybp ybr yby yca ycc ycp ycy ypa yra yrc yrp yyb yyc yyy