c-- ccc cce cco ccp cct ccx ce- cec cee ceo cep cet cex co- coc coe coo cop cot cox cpc cpe cpo cpp cpt cpx ctc cte cto ctp ctt ctx cxc cxo cxp cxt cxx ec- ecc ece eco ect ecx eec eee eeo eep eet eex eo- eoc eoe eoo eop eot ep- epc epe epo epp ept epx etc ete eto etp ett etx ex- exc exe exo exp ext exx oc- occ oco ocp oct ocx oec oee oeo oep oet oex oo- ooc ooo oop oot oox op- opc ope opo opp opt opx ot- otc ote oto otp ott ox- oxc oxo oxt oxx p-p pcc pce pco pcp pct pcx pec pee peo pep pet pex poc poe poo pop pot pox ppc ppe ppo ppp ppt ppx pt- ptc pte pto ptp ptt ptx pxc pxe pxt t-x tcc tce tco tcp tct tcx te- tec tee teo tep tet tex to- toc toe too top tot tox tpc tpe tpo tpp tpt tpx ttc tte tto ttp ttt ttx txe txt xcp xcx xee xep xet xex xoc xoo xop xot xox xpc xpe xpo xpp xpt xtc xtp xtx xxo xxp xxx