a-a a-b aaa aab aad aap aar aas ab- aba abb abd abp abr abs ad- ada adb add adp adr ads ap- apa apb apd app apr aps ar- ara arb ard arp arr ars as- asa asb asd asp asr ass b-p baa bab bad bap bar bas bba bbb bbd bbp bbr bbs bda bdb bdd bdp bdr bds bpa bpb bpd bpp bpr bps bra brb brd brp brr brs bsa bsb bsd bsp bsr bss daa dab dad dap dar das dba dbb dbd dbp dbr dbs dda ddb ddd ddp ddr dds dpa dpb dpd dpp dpr dps dra drb drd drp drr drs dsa dsb dsd dsp dsr dss p-p paa pab pad pap par pas pba pbb pbd pbp pbr pbs pda pdb pdd pdp pdr pds ppa ppb ppd ppp ppr pps pra prb prd prp prr prs ps- psa psb psd psp psr pss ra- raa rab rad rap rar ras rba rbb rbd rbp rbr rbs rda rdb rdd rdp rdr rds rpa rpb rpd rpp rpr rps rra rrb rrd rrp rrr rrs rsa rsb rsd rsp rsr rss saa sab sad sap sar sas sba sbb sbd sbp sbr sbs sda sdb sdd sdp sdr sds spa spb spd spp spr sps sr- sra srb srd srp srr srs ss- ssa ssb ssd ssp ssr sss