-er c-- ccc cce cch cco ccr ccx ce- cec cee ceh ceo cer cex ch- chc che chh cho chr chx co- coc coe coh coo cor cox crc cre crh cro crr crx cxc cxh cxo cxr cxx ec- ecc ece ech eco ecr ecx eec eee eeo eer eex ehc ehe ehh eho ehr eo- eoc eoe eoh eoo eor erc ere erh ero err ex- exc exe exh exo exr exx hcc hce hch hco hcr he- hec hee heh heo her hex hhc hhe hhh hho hhr hoc hoe hoh hoo hor hox hr- hrc hre hrh hro hrr hxc oc- occ och oco ocr ocx oec oee oeh oeo oer oex ohc ohe ohh oho ohr oo- ooc ooh ooo oor oox or- orc ore orh oro orr orx ox- oxc oxo oxx rcc rce rch rco rcr rcx re- rec ree reh reo rer rex rh- rhc rhe rhh rho rhr roc roe roh roo ror rox rrc rrh rrr rxr xch xcr xcx xee xer xex xoc xoo xor xox xrc xrx xxo xxx