-er a-a a-b a-c aaa aab aac aad aae aak aap aar ab- aba abb abc abd abe abk abp abr ac- aca acb acc acd ace ack acp acr ad- ada adb adc add ade adk adp adr aea aeb aec aed aee aek aep aer aka akb akc akd ake akk akp akr ap- apa apb apc apd ape apk app apr ar- ara arb arc ard are ark arp arr b-p baa bab bac bad bae bak bap bar bba bbb bbc bbd bbe bbk bbp bbr bca bcb bcc bcd bce bck bcp bcr bda bdb bdc bdd bde bdk bdp bdr be- bea beb bec bed bee bek bep ber bka bkb bkc bke bkk bkp bkr bpa bpb bpc bpd bpe bpp bpr bra brb brd bre brk brp brr c-- caa cab cac cad cae cak cap car cba cbb cbc cbd cbe cbk cbp cbr cca ccb ccc ccd cce cck ccp ccr cda cdb cdc cdd cde cdk cdp cdr ce- cea ceb cec ced cee cek cep cer cka ckb ckc ckd cpa cpb cpc cpd cpe cpk cpp cpr cra crb crc crd cre crk crp crr daa dab dac dad dae dak dap dar dba dbb dbc dbd dbe dbk dbp dbr dca dcb dcc dcd dce dck dcp dcr dda ddb ddc ddd dde ddk ddp ddr de- dea deb dec ded dee dek dep der dka dkb dkc dke dkk dkp dkr dpa dpb dpc dpd dpe dpk dpp dpr dra drb drc drd dre drk drp drr eaa eab eac ead eae eak eap ear eba ebb ebc ebd ebe ebk ebp ebr ec- eca ecb ecc ecd ece eck ecr ed- eda edb edc edd ede edk edp edr eea eeb eec eed eee eek eep eer eka ekb ekc ekd eke ekp ekr ep- epa epb epc epd epe epp epr era erb erc erd ere erk erp err ka- kaa kab kac kad kae kak kap kar kba kbb kbc kbd kbe kbk kbp kbr kca kcb kcc kcd kce kck kcp kcr kda kdb kdc kde kdk kdp kdr ke- kea keb kec ked kee kek kep ker kkb kkc kke kkk kkp kkr kpa kpc kpd kpe kpk kpp kpr kra krc krd krk krp krr p-p paa pab pac pad pae pak pap par pba pbb pbc pbd pbe pbk pbp pbr pca pcb pcc pcd pce pck pcp pcr pda pdb pdc pdd pde pdk pdp pdr pea peb pec ped pee pek pep per pka pkb pkc pkd pke pkp pkr ppa ppb ppc ppd ppe ppk ppp ppr pra prb prc prd pre prk prp prr ra- raa rab rac rad rae rak rap rar rba rbb rbc rbd rbe rbk rbp rbr rca rcb rcc rcd rce rcp rcr rda rdb rdc rdd rde rdp rdr re- rea reb rec red ree rek rep rer rkb rkc rke rkk rkp rpa rpb rpc rpd rpe rpk rpp rpr rra rrb rrc rrd rrk rrp rrr