-er -ic c-- ccc cce cci cco ccr ccx ce- cec cee cei ceo cer cex ci- cic cie cii cio cir cix co- coc coe coi coo cor cox crc cre cri cro crr crx cxc cxi cxo cxr cxx ec- ecc ece eci eco ecr ecx eec eee eeo eer eex eic eie eii eio eir eix eo- eoc eoe eoi eoo eor erc ere eri ero err ex- exc exe exi exo exr exx icc ice ici ico icr ie- iec iee iei ier iex iic iie iii iio iir iix io- ioc ioe ioi ioo ior ir- irc ire iri iro irr irx ixc ixe ixi o-i oc- occ oci oco ocr ocx oec oee oei oeo oer oex oic oie oii oio oir oo- ooc ooi ooo oor oox or- orc ore ori oro orr orx ox- oxc oxi oxo oxx rcc rce rci rco rcr rcx re- rec ree rei reo rer rex ric rie rii rio rir rix roc roe roi roo ror rox rrc rri rrr rxr xci xcr xcx xee xer xex xic xie xii xio xix xoc xoi xoo xor xox xrc xrx xxi xxo xxx