-er a-a a-c aaa aac aad aae aap aar aas aax ac- aca acc acd ace acp acr acs acx ad- ada adc add ade adp adr ads adx aea aec aed aee aep aer aes aex ap- apa apc apd ape app apr aps apx ar- ara arc ard are arp arr ars arx as- asa asc asd ase asp asr ass asx ax- axa axe axp axr axs axx c-- caa cac cad cae cap car cas cax cca ccc ccd cce ccp ccr ccs ccx cda cdc cdd cde cdp cdr cds cdx ce- cea cec ced cee cep cer ces cex cpa cpc cpd cpe cpp cpr cps cpx cra crc crd cre crp crr crs crx csa csc csd cse csp csr css csx cxc cxp cxr cxs cxx daa dac dad dae dap dar das dax dca dcc dcd dce dcp dcr dcs dcx dda ddc ddd dde ddp ddr dds ddx de- dea dec ded dee dep der des dex dpa dpc dpd dpe dpp dpr dps dra drc drd dre drp drr drs drx dsa dsc dsd dse dsp dsr dss dsx dxc dxd dxp dxr dxs dxx eaa eac ead eae eap ear eas eax ec- eca ecc ecd ece ecr ecs ecx ed- eda edc edd ede edp edr eds edx eea eec eed eee eep eer ees eex ep- epa epc epd epe epp epr eps epx era erc erd ere erp err ers es- esa esc esd ese esp esr ess esx ex- exa exc exd exe exp exr exs exx p-p paa pac pad pae pap par pas pax pca pcc pcd pce pcp pcr pcs pcx pda pdc pdd pde pdp pdr pds pdx pea pec ped pee pep per pes pex ppa ppc ppd ppe ppp ppr pps ppx pra prc prd pre prp prr prs prx ps- psa psc psd pse psp psr pss psx pxc pxe pxr pxs ra- raa rac rad rae rap rar ras rax rca rcc rcd rce rcp rcr rcs rcx rda rdc rdd rde rdp rdr rds rdx re- rea rec red ree rep rer res rex rpa rpc rpd rpe rpp rpr rps rpx rra rrc rrd rrp rrr rrs rsa rsc rsd rse rsp rsr rss rsx rxp rxr rxs saa sac sad sae sap sar sas sax sca scc scd sce scp scr scs scx sda sdc sdd sde sdp sdr sds se- sea sec sed see sep ser ses sex spa spc spd spe spp spr sps spx sr- sra src srd sre srp srr srs srx ss- ssa ssc ssd sse ssp ssr sss ssx sxc sxs xaa xac xad xap xar xas xcd xcp xcr xcx xda xdc xde xdr xds xed xee xep xer xes xex xpa xpc xpd xpe xpp xps xrc xrd xrx xsa xsc xsp xss xxp xxx