-er -ic a-a a-b a-c a-i aaa aab aac aae aai aao aar ab- aba abb abc abe abi abo abr ac- aca acb acc ace aci aco acr aea aeb aec aee aei aeo aer ai- aia aib aic aie aii aio air aoa aob aoc aoe aoi aoo aor ar- ara arb arc are ari aro arr baa bab bac bae bai bao bar bba bbb bbc bbe bbi bbo bbr bca bcb bcc bce bci bco bcr be- bea beb bec bee bei beo ber bi- bia bib bic bie bii bio bir boa bob boc boe boi boo bor bra brb bre bri bro brr c-- caa cab cac cae cai cao car cba cbb cbc cbe cbi cbo cbr cca ccb ccc cce cci cco ccr ce- cea ceb cec cee cei ceo cer ci- cia cib cic cie cii cio cir co- coa cob coc coe coi coo cor cra crb crc cre cri cro crr eaa eab eac eae eai eao ear eba ebb ebc ebe ebi ebo ebr ec- eca ecb ecc ece eci eco ecr eea eeb eec eee eeo eer eia eib eic eie eii eio eir eo- eoa eob eoc eoe eoi eoo eor era erb erc ere eri ero err ia- iaa iab iac iae iai iao iar iba ibb ibc ibe ibi ibo ibr ica icb icc ice ici ico icr ie- iea iec iee iei ier iia iib iic iie iii iio iir io- ioa iob ioc ioe ioi ioo ior ir- ira irb irc ire iri iro irr o-i oaa oab oac oae oai oao oar ob- oba obb obc obe obi obo obr oc- oca ocb occ oci oco ocr oea oeb oec oee oei oeo oer oia oib oic oie oii oio oir oo- ooa oob ooc ooi ooo oor or- ora orb orc ore ori oro orr ra- raa rab rac rae rai rao rar rba rbb rbc rbe rbi rbo rbr rca rcb rcc rce rci rco rcr re- rea reb rec ree rei reo rer ria rib ric rie rii rio rir roa rob roc roe roi roo ror rra rrb rrc rri rrr