-er a-a a-c a-t aaa aac aad aae aar aat aax ac- aca acc acd ace acr act acx ad- ada adc add ade adr adt adx aea aec aed aee aer aet aex ar- ara arc ard are arr art arx at- ata atc atd ate atr att atx ax- axa axe axr axt axx c-- caa cac cad cae car cat cax cca ccc ccd cce ccr cct ccx cda cdc cdd cde cdr cdt cdx ce- cea cec ced cee cer cet cex cra crc crd cre crr crt crx cta ctc ctd cte ctr ctt ctx cxc cxr cxt cxx daa dac dad dae dar dat dax dca dcc dcd dce dcr dct dcx dda ddc ddd dde ddr ddt ddx de- dea dec ded dee der det dex dra drc drd dre drr drt drx dta dtc dtd dte dtr dtt dtx dxc dxd dxr dxt dxx eaa eac ead eae ear eat eax ec- eca ecc ecd ece ecr ect ecx ed- eda edc edd ede edr edt edx eea eec eed eee eer eet eex era erc erd ere err ert eta etc etd ete etr ett etx ex- exa exc exd exe exr ext exx ra- raa rac rad rae rar rat rax rca rcc rcd rce rcr rct rcx rda rdc rdd rde rdr rdt rdx re- rea rec red ree rer ret rex rra rrc rrd rrr rrt rta rtc rtd rte rtr rtt rtx rxr t-x taa tac tad tae tar tat tax tca tcc tcd tce tcr tct tcx tda tdc tdd tde tdr tdt tdx te- tea tec ted tee ter tet tex tra trc trd tre trr trt trx tta ttc ttd tte ttr ttt ttx txe txt xaa xac xad xar xat xcd xcr xcx xda xdc xde xdr xdt xed xee xer xet xex xrc xrd xrt xrx xtc xtr xtx xxx